Ford F-150 - 1997-2003 :: Truck Stumbles - RPMs Drop When In Gear
Oct 23, 2012
I have a 1997 forkd F150 with a 4.6L Romeo engine. I have recently rebuilt the engine and now since it is put back together I am having a issues that i cannot pin point. When the truck is running and in gear my RPM drop to around 500 or below and my oil pressure drops and comes back up when the rpm's come back up this an intermittent problem and I have replaced the IAC valve and every once in a while i get a P0401 code for the exhaust recirculation. I think I am loosing some kind of vacuum. It was not doing this when I tore into the truck. It seems to be running okay not hesitation.
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95 explorer 4.0l ohv. I go to take off and then come to a stop after about 10-15 feet, i just give it a little gas then lightly press the brake, rpm's drop to around 400-500 then back to normal. I have replaced:
IAC
MAF
Plugs & wires
Coil pack
intake manifold gaskets
fuel system cleaner
fuel filter
air filter
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Two weeks ago Sun, truck ran fine, however Mon morning all hell broke loose. Truck was running very sluggish and stalling while coming to a stop. My first thought was tune up. I replaced the plugs and wires. During this I found that i could not get a socket around the ever loved driver side rear plug so i was only able to replace 7 plugs however in that process i managed to break the metal coolant tube that runs to the heater core.
Aday later replaced the entire intake manifold,egr valve, egr tube, IAC valve, both coil packs, fuel filter, tranny fluid and filter. During the removal of the intake i looked at the rear spark plug and found that a screw had been wedged into the hole breaking the plug and got it changed now it is all back together and the truck runs amazing however did not solve the low rpms during stopping. ive replace the above and checked fuel pressure which is good.
I have a TPS sensor just haven't installed it yet not sure if it is related to the issue. Tranny guy says it may be a bad solenoid or TC however last night I reset the PCM and drove it it ran flawless. this morning the problem returned which leads me to believe its not the tranny. ok one last kicker that 6 experts have failed to answer when i manually put the truck into 2nd gear the engine dies! no studder no fighting just quits.
Truck is a 98 F150 4.6 V8 186,000 miles i have yet to
1) change TPS.
2) clean throttle body.
3) clean MAF sensor. n
Not sure if any of this has an effect on the issue. There is only a EGR insufficient Air flow code..
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So I know there has been lots of posts on surging issues and how to troubleshoot. My truck is a 97 f150 4x4 xlt 4.6l v8. I have noticing surging and dropping in my RPMs lately. No CEL. I have kept a journal when I notice when it happens. I only have issues when I am driving around 40-50 mph and if I go over bumps/pot holes/rough spots in roads or when I'm braking over bumps/pot holes/rough spots, my truck surges/RPMs drop CEL flashes on and off only during these instances. Makes me think something could be loose or something causing this. It has stalled at times when having to brake fast (yellow light, etc.). Where to look first? 1997 F150 4x4 4.6 V8...
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I have a 1997 F-150, 2 wheel drive, 4.6L truck. Recently the transmission got to where it didn't shift properly. Then it got to where, after driving it about 10 to 15 miles the transmission would drop out of gear with the transmission selector in drive.
I have replaced the transmission sensor, the rear end sensor and it still does the same thing. Drive about 10 to 15 miles and, with the transmission selector in drive the truck will not pull. The motor can be rev'ed but the truck won't move just like it was in neutral.
What is wrong. The transmission shifts fine, the truck runs fine, but after 10 to 15 miles the transmission quits working.
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4R70W. This one is in my 99 F-150 with the 4.6. From what the previous owner told me this trans only has 13k miles on the rebuild and I believe him because the converter is bright blue and when it does shift right, the shifts are solid and fluid is very clean. Truck only has 98k miles on the body as well, so it's possible the truck did sit a while because my tires have a ton of tread on them, but they are dry rotted a bit (dated 2006 IIRC).
Issue: When the trans is cold (sat overnight) it will shift to neutral between the 2-3 shift for 1-3 seconds depending on outside temperature and then drop into gear. But it only does this for the first 30 seconds or so of driving, after that it shifts normal (although it does seem to hold gears a little longer than I would think it should on occasion and not upshift). I have only gotten it to do it once per cold start so it seems like once the trans gets any heat it's fine.
I was also thinking I was getting drain back and maybe it wasn't heat related so I dropped the pan, replaced the filter, fluid and pan seal (it had a small leak) and torqued the valve body. Two of the bolts were a little loose, but the rest were fine. Tightened them to spec and put it back together with no dice. Truck also gets pretty bad fuel mileage so I'm starting to think maybe there is some temp sensor screwing everything up?
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Just finished putting a fresh 460 backed by a (1977) c6 in my '68 ranger and now I'm having (what I believe is) transmission problems. The truck will idle and rev properly in gear but as soon as I put it in drive or reverse the RPM's drop and it dies. I jacked the back end up and put it in both drive and reverse and the tire's spin, but if I try and apply the brake to stop them the truck will die. My suspicion is that the torque converter is locked up all the time. I have managed to get it in gear and give it gas and it'll drive and shift fine, until I come to a stop. My question, what would cause the converter to do this? It's the same transmission and converter that I pulled out a month ago and I never had any issues before...
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If I don't keep in the throttle immediately after start up it will stall a lot of the time. It doesn't do this every time or if it sits for a while but if I drive it and then stop off at a store or something and then go to start it back up it gives me this problem. I notice it idles about 3-4k RPM's when I stop at a light or something too.
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So my "farm truck" is idling very rough, to the point that sometimes that it stalls out. At high idle it runs fine but when its at a idle its very rough. Its been running fine until probably a month ago or so and its just getting worse. What it could be? I am thinking it might be that something is dirty but i just dont know where to start with figuring out what the problem is.
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So my 98 f150 xlt 4.6 is having a issue where the truck is jumping from 1500 rpm to about 2500 - 2600 rpm. You know sitting there trying to get up to speed. then all the sudden i look down and its at 1500 rpm. but still not really going anywhere. So i give it a little more throttle or gas and it jumps from 1500 to about 2500. Its been like this for a month but i thought it was crap fuel. What is the cause or maybe a solution?
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I'll try not to post an entire book.. But I bought a 2000 F250 not even 8 months ago, it did have issues before but I changed out the spark plugs and coils and it fixed it's original missing issues.. I also just recently changed the fuel filter but it didn't fix it's new problem.. It drives ok around town but if I get over 35 mph it doesn't run well... If I try to keep a steady foot on the gas but don't get the RPMs over 2000, the RPMs will stay where they're at for just a second then they will drop down and the whole truck starts shaking.. I push more on the gas and it shakes even more and the RPMs don't move at all until I really step on it.. It lacks in power going up hills as well... The dealership i bought it from said the Catalytic Converter was bad but my uncle who is a mechanic says it isn't.. It's the first vehicle I've bought so kinda wanna make it last..
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Twice now this has happened to me and I'm concerned it will become worse if I don't fix it. Driving down the road my engine has disengaged. By this I mean the vehicle both times has been at 55 MPH, my foot on the throttle rpms riding around 1300 revolutions, and the engine disengages rpms drop below idle and my "wait to start" light comes on. This both times lasts approximately 2 seconds and throttle reengages while still traveling 55 MPH, "wait to start" light goes off and its like it never happened. What's going on with my truck? Ford diesel 97 250 7.3 ...
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I had what I was told was the breather (on the drivers side valve cover) snap off. I was able to place a piece of tubing In it and reconnect it. I had to change the #7 cylinder spark plug wire. Got a misfire code and found the wire was loose and corroded. Replaced wire and PVC valve.
My problem is, it seems not to be idling as fast as it was before this happened. The truck stalls out now in gear but not in park. 1997 F150 4.6 ....
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2002 F-150 4.2L. About a year ago, it threw the P0171 and 0174 codes up. After replacing all the simple stuff, I bit the bullet and replaced the lower intake gasket as well as the upper intake gaskets. Buttoned it all up, reset the codes and we were back in business. No issues, truck ran good. About 6-8 months later, the check engine light came back on, I check it and it was that pesky set of codes again, 0171 and 0174.
It still ran fine, but the codes were there, so I just drove it for a while (it's a company truck that doesn't get driven that much).
A couple of weeks ago while driving it, it acted very sluggish. You could mash the accelerator and it would just very slowly run up the speed. It never hesitated or missed, it just got very very sluggish. Checked the codes, no additional codes.
Then it began to stumble when you mashed the gas.
I put new plugs (old one's looked great, other than a huge gap), new wires, new coil pack and started it. Pushed the gas pedal, it just dies.
I look for obvious vacuum leaks and replace a couple of elbows for the PCV and it seems to run a little better. Enough so that I can drive it, but still not running right.
I ordered all the intake gaskets and new isolator bolts and spend Saturday pulling that apart. I didn't do the lower intake because the upper intake gaskets looked so good, I just don't believe this is a intake gasket problem. None the less, I installed the new gaskets on the plenum and upper intake, new isolator bolts, replaced a couple pieces of vacuum hose that looked cracked, started it back up, it ran as smooth as silk.
Convinced I had it fixed, I went for a test drive. Idling, it is as smooth as you could ask for. Pull up to a stop sign, wait, step on the gas and it chokes. Just stumbles and you can hear it almost backfiring and pushing air back through the system.
I've put new PCV, new EGR, new vacuum lines in several places, new upper intake gaskets, new plenum gaskets, new isolator bolts, and even new o-rings on the injectors, and I'm still getting the 0171 and 0174 codes.
With the diagnostics on, I can see voltage varying on all O2 sensors, so I assume they are working (none of them are reading 0 volts). It doesn't throw any other code up, other than the 0171 and 0174.
At this point I feel like I'm replaced every single thing ever mentioned in any 0171 and 0174 thread on the internet. Where to go next? 1 more point, if you very slowly push the gas, it runs fine, but any pressure on it, it bogs down and just stumbles.
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Well here it is I just put a new slave cylinder in my 02' F-150 and once we figured out all the little issues we were having we finally got the truck to fire up!!! Now my problem is that when the truck is running I can't get the truck into gear with the clutch pushed and it doesn't even grind. But when the truck is off it goes through the gears no problem what so ever. When we did the slave cylinder while we were in there we just replaced everything clutch, pressure plate, flywheel, rear seal, and pilot bearing. We figured that since all the shops were quoting me 800 and up for just doing the slave that since were in there we might as well do everything since nothing has ever been replaced yet. My question is why will the truck not let me shift into gears when running but no problem when off. Oh and yes the system was bled after doing the slave actually twice so far.
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I have a 1997 Ford F-150 with the 4.6L auto trans 189,000 miles
Ok.. there was no problems until the other day when I unplugged the positive side of the battery to replace it's clamp. I Put the new one on and drove to the store but when I came to a stop, the rpm's dropped to 0 and the truck died. I restarted it and every time I would come to a stop it would die unless I give it a little gas also if I start the truck and leave it in park it idles fine until I give it some gas then let off.. the idle drops and dies! If I give it a little steady gas the idle will return to normal.
The check engine light works fine but never once lit up because of this problem! I used a code scanner and if the truck was off and the key forward, it would have no codes. With it running it had the code P0443. I found and replaced a blown fuse and still have the same problem but it reads no codes at anytime. I checked all the vacuum hoses and there seems to be no leaks and the mass airflow sensor looks clean. I have allot of miles but it has been taken care of well and has had a ton of parts replaced over the last few years.
I am wondering why this happened out of the blue and If there is something I am missing that I should be looking at. I don't want to replace the purge control valve if thats not the problem.
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1999 f150 5.4 it's been over 3 months since It happened I hit a pretty big mud hole and right after it starts bogging and running rough and won't drive I made it home and second and I've been driving it around town in second gear since. I've been trying different things since it happened, It runs rough in drive, reverse, neutral, and first (towing gear) but revs up just fine in second (towing gear).
So far I've
- Checked all fuses
- Changed plugs checks coil packs
- Dropped pan changed tranny fluid and filter
I broke a heater core line so I replaced the intake manifold and got a good look at everything and cleaned it out
- Cleaned throttle body
- Checked all connections
- Checked all vacuum hoses
- Replaced maf sensor
- Pulled the codes but I don't have them handy.
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I come over from the old school forum (48-60) with a question about a new to me 1999 F150 XLT 5.4L, 4x4, Auto. Truck has ran awesome for a couple of days. Truck has in excess of 410,000 miles but don't let that mislead. I believe the engine has been replaced sometime along the way. Yesterday I was driving and it just stumbled and stopped. After sitting for 5 minutes it started again, stumbled and stopped.
Today I checked the following:
- Fuel pump/relay - both work
- Dropped gas tank and replaced fuel pump strainer and fuel filter
- Fuel pressure at rail remains steady
- No codes present and no SES/CEL on.
Could this be a plugged EGR valve or IAC valve? I have had similar issues on Tauruses but it always threw a code when it did. Could this indicate a cat issue?
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I am not sure if it's my imagination or not, but my car seems to be running differently lately.
When the car shifts into 4th the Rpms seem to drop kind of and the car seems like it is bogging down. Not extreme, but I don't remember this when I first got it. It's like I really have to accelerate when it shifts into 4th or I cannot pick any speed up.
Is it because the motor is now broken in? It has right at 8,000 miles now. It's due for an oil change, but I wouldn't think that would have anything to do with it !
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This 97 F150 4.2 is new to me, originally a very base 2wd white fleet vehicle, with 189,000 miles, runs smoothly and quietly, idles well, transmission shifts smoothly. Gets reasonable gas mileage.
Problem statement: the truck has an intermittent starting problem. The failure to start happens about 5-10% of the time. The motor will turn over fine, but but immediately stumbles while trying to start. Turn key off and then re-start attempt will be again followed by a bucking stumble. Some times the motor might try and run for 2-3 seconds bucking and stumbling. It is possible the problem happens more often when the truck is warm and has been shut off for 15 minutes or so. Once the problem happens it is very repeatable. It won't start again unless I wait about 30 minutes to an hour. Once it starts it seems to run very nicely. I have noticed some times when I go to successfully start the truck it might run roughly for the first 3-4 seconds bucking and sputtering a bit and then smooth out and not have an issue until the next re-start attempt.
The truck runs so nicely when it is running I doubt it is an issue with the plugs, air filter general tune up. Could it be an intermittent fuel pump issue? The next time it occurs I will check fuel pressure. Could it be fuel pressure regulator? Also tested by fuel pressure. ECU? The truck runs very nicely most of time that seems like a long shot. Crank sensor? Bad fuel? I did add some dry gas.
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My 02 F150 4.6 has 84K miles on it, and started stumbling/hesitating during accellartion about three weeks ago. Before this problem started (about 2,000 miles ago), I installed a new fuel filter and air filter. Since I noticed the problem, I installed new plugs. The problem didn't go away, so today I checked the fuel pressure. At idle the pressure is 32psi with the vacuum line left on the fuel pressure regulator (30-45 is normal as per Chilton's), and 42 with the vacuum line off (40-50 is normal as per Chilton's). I also had someone else rev the engine so I could observe, and found that the fuel pressure went as low as 28 when the engine speed was quickly increased. The standing fuel line pressure is 30 (30 is normal as per Chilton's) Does this sound like a fuel pump problem, or is there something else that I'm missing.
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