Ford F-150 - 1997-2003 :: 1999 - Engine Stumble At Load
Oct 13, 2007
1999 4.6 (106K miles) will stumble / miss when at 35-50 mph under a mid throttle load (just before reaching the downshift point). Has been doing this since I bought the truck at 70K miles.
Computer has no codes, engine runs fine under all other circumstances, and gets a decent ~20 MPG on the highway.
Done the standard tune up items (plugs / motocraft) and cleaned MAF, replaced TPS, tranny flush/ filter. Replaced the left O2 sensor 2 months ago, but it dumped a code and was really noticeable when it went out.
I am about ready to dive off and replace the MAF, but at $100 a shot would like other alternatives to try first. I am really convinced the engine is leaning out and misfiring under this load.
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It has been since the 80's that I have attempted to do any work on a vehicle. How do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents. I have an 2000 F150 with the large engine with about 112,000 miles.
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I have a 2002 Ford F-150 with a 5.4 Triton. 212,xxx miles. I replaced the cops and the plugs about 6 months ago. I was pulling a trailer up hill last week and the engine was under a load doing about 3000rpm. It began to misfire and give me a flashing mil. However, before I went very far the engine began to run fine. It happened 3-4 different times. However, there is no code recorded. I've driven the truck nearly 100 miles with no problems, but I'm going to be pulling that trailer uphill again next week.
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I recently bought a 2000 f150 4.6 with 105000 on it I notice when I was driving if the engine got under a load it whined. It does it every time and it does it being parked but not as bad. What it could be?
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I only hear it in gear under load so I can't stick my head under the hood to pin point it. I dont see any black streaks and I replaced the EGR tube. Is it commonly just the gasket or do the manifolds crack? If they crack where?
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I have a 2002 f150 with a 5.4. It runs bad but all the data looks good. When you rev it in gear it revs sluggishly but when you put it in drive and give it any gas it will stumble and try to die. Un plug the tranny and it revs great and when in gear it runs great, but it obviously is stuck in second gear. I have codes for tcc short, solenoids a and b short, tcc short, and pressure control solenoid. I have replaced all of these parts inside the tranny including the wiring harness and main connector (transmission side). The OD light is also flashing. I Have run out of stuff to replace, obviously its something transmission related if the truck runs fine with it unplugged.
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I have a 97 F150 4.6. The truck has developed a slight stumble/misfire when under acceleration. Once at speed it runs fine. It has not given any codes. I've checked for them several times. The plugs and wires have been changed. Is it possible that a coil pack could be bad without throwing a code?
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First, a little background on my truck. 2007 with 5.4, 122000 miles, oil changes with 5-20 Motorcraft and Motorcraft filters, plugs done by dealer 40000 miles ago. The truck has developed a ticking noise, kind of like a lifter (I know these engines don't have lifters) that is most noticeable from the side of the truck near wheel. ticking speeds up with the rpm. Also around same time, between 40-55 under load there is a bit of a stumble, but I can gas thru it. I'm guessing these are related. I'm thinking spark plugs again, but shouldn't I get more than 40000 out of them? I might just take it in, since I've got oil leak somewhere around back of the oil pan, but figured maybe might get some clues first. Also, no CEL.
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2003 F150 5.4 72852 miles
I have a Rough Idle & sometimes a hesitation or stumble on acceleration. I cleaned the MAF & IAC motor & Air & Fuel Filters are new. I got a 20890 scanner & ran test 6 53 as suggested in many posts by BlueGrass. Here are My results & what They Convert to.
1 00F5 .3675
2 0051 .1215
3 0000
4 0000
5 00A3 .2445
6 0000
7 0000
8 0000
I'm guessing the cop's are ok & probably need plugs? I was hoping to just swap a coil. Too cold to do plugs & truck won't fit in my garage.
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A friend from work is having what he says is piston slap, but only under a load. I feel it could be the timing set since it's never been changed and at least 160k miles. Odometer quit working at least 5 years ago. Other than that, motor runs great. 1997 F150 4.6....
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I have 2001 F-150 with 4.6L. Truck runs fine until under load and runs fine until I slow down to a stop sign. Once truck sits for a few moments it fires up again and will run for a short while then will do it again. Each time i let it sit for a few minutes, it will start again.
I pull a small travel trailer and seems to happen more frequently when pulling or climbing hill, but not under full power, just when slowing down. Could this be cause of catalytic converters? MAF sensor, or fuel starving.
Check engine light is on, will codes identify if it is a plugged cat?
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My 4.2 liter F150 suddenly started missing under load. A little background: It is a late 2003 and has 75k miles. It has been in my family since new, and I have had it for the last 4 years. This truck is as stock as they come, and has been well maintained.
On my way to work yesterday, it began missing. Not bad at first, but got worse. It misses while under load and under acceleration. The "check engine light" never came on. I have not put fuel in in several days, and it ran fine until now, so I doubt it is bad fuel. I started the engine after dark and looked for arcing. None visible, and I even sprayed the wires with a mist of water. I pulled the plugs and they all look normal. The gaps were all way too large, so I regapped the plugs to .054". I pulled the coil pack and it checks within range with my VOM. Can the coil pack be the problem even though it checks out on the bench? Can the large plug gaps have contributed to a coil pack failure?
Where to start. I HATE just throwing parts at this thing, and I don't like wasting money... If I let one of the auto parts stores run a scan, will it show a code even though I have no check engine light? I used to think of myself as a pretty good diagnostician, but then again, when I used to spend a lot of time under the hood, those cars had points, condensers and carburetors...
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My daughter has a 2010 F150 with 5.4, when pulling her horse trailer or extended idling her truck starts running rough, so far her husband has changed the fuel pump and 2 coil packs, no luck.
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Bought the truck 1000 miles from home, ran great, checked oil it was black and well used, coolant was milky and degas bottle had some pressure in it.
Drove 200 miles fine, 75mph lots of power, no smoke, no overheating.
While cruising felt slight stumble, and lost hot air from the heater (started blowing cold), saw temp needle move slightly (still under 1/2 mark) and pulled over. Truck stalled on the offramp, and I was not able to get it to fire. I checked oil and it was same dark black. Coolant was low, down to about 2.5 gallons.
Towed it home, oil change, coolant flush, new thermostat, rebuilt IPR, and it fired right up. Ran great, smooth. Noticed slight haze out of the exhaust at idle, and puffs of white smoke when on throttle. Checked oil and it was milky. Where to look?
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I have a 03 f150 2wd with the 4.6l. Recently it has been slow shifting into reverse(about 2 full seconds) and when it finally gets in reverse it shudders when it comes under load. The fluid is full and not burnt...
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Have a p0401 code which I need to diagnose and solve. However, I don't believe the symptoms are indicative of the EGR system. Its a 1999 4.6L auto approximately 200k miles. Truck runs fine until it warms up, and then occasionally it begins to act like its missing under load. steady state on the freeway it may have an occasional miss, but put a load on the motor and the miss becomes real bad. This doesn't seem to me to be symptomatic of a P0401 code, but I don't really understand the EGR system enough to be sure. Searching on the forums for other p0401 codes doesn't seem to have the same symptoms.
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I've got a 97 truck, broke the crank, swapped in a motor from an 07. Heads down is 07, intake up is 97. had heads planed and a valve job with new seals done. Left it alone from the rings down. Got it in this weekend, running today. Ran it in the driveway with no load for about 30 minutes, top end was noisy for about 5 minutes till the top end got good and oily (I'm assuming). Purred like a kitten, sounded real smooth. Took it for a drive around the block, heard the clatter in the video below. It's almost always there when driving. Brought it back, turned it off to check oil, it was a quart low. Added oil, startup was VERY labored with a real hard knock in the bottom end. Ran like poo till I gave it some throttle for a couple seconds, then it cleaned up and idled well. Let it run for a couple minutes, turned off and let it sit for a couple minutes then started back up, same thing. Very labored with hard knocking.
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A bit about my truck : 2001 F250 CC SB 4x4 175k miles
Wicked wheel, 6637 filter, DP tuner, Summit 5" exhaust, pressure regulator somewhere in the boost circuit to fool the computer a bit....
Every few times I drive the truck it will stumble and maybe even stall. The issue feels something like a CPS problem, although I've swapped out a few CPS to see if I by chance had a bad one in the engine as well as a bad one in the glove box. No changes. I was driving home from work one afternoon and it was running particularly bad. I stopped off at a local garage (who doesn't work on diesels and was reluctant to plug in....but did because he's a nice guy).
He plugged in with his snap-on tool and came up with P0603 and P1211. The P0603 seems to be nearly inevitable with a tuner. Check P1211 sounds like it could be an issue with a number of things, but I tried to attack the free and cheap issues first. I dropped my tank and had a look inside. I was hoping to find a squirrel wrapped around the sending unit, but there was a disappointingly small amount of crud. I cleaned it up and put it back in, then changed my fuel filter. No improvements.
So I decided to get with the program and buy AutoEnginuity. Got it. Even did some reading in class and did the initial homework assignment on page 2 or 3. Seems like the best thing to do it hook up, set up some parameters to monitor, and drive around recording until the problem happens. But.........what parameters do I want to monitor? I don't want to overtax the OBDII bus with too many requests such that my data looks like crap.
A few other things............ In the last year I swapped out the valve-cover gaskets & harnesses with an all-in-one molded setup. About a month back I replaced the exhaust back pressure sensor and tube.
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I have a 97 F150, 2wd, 4.6, auto bought for a great price agout 3 months ago.... I installed a cold air intake (air raid) and a throttle body spacer with the swirling cuts.
Since the cold air intake add, the truck occasionally makes a load "roaring" sound from the intake system. At same time rpms increase 500-1000 rpms...
it doesn't do it all the time, mostly at low throttle, and a quick jab on the accelerator usually stops it. sometimes such as when parking, holding the brake and applying a bit of throttle with load from the brake will also stop it.
Guys at local garage seem to think it has something to do with lower outside temps, (denser) and addition of cold air intake. it made the noise before the throttle body spacer.
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I have a 1998 F150 5.4L 4WD with 192k mi on it. Recently ( suddenly ) the vehicle began shuttering pretty alerting under light load at 35 - 45mph. The engine idle was intermittently smooth then rough. I quickly drove the truck home and ran a Trouble Code check with my Autoxray EZ-scan 4000 and found the two trouble codes P0302 and P0171. I have checked for vacuum hose cracks and found none.
Replaced the fuel filter, PCV valve, and cleaned the MAF sensor ( dirty ).
Right after cleaning the MAF sensor the idle remained smooth - but stumbling immediately when put in drive. Driving at 35-45mph still exhibits intermittent shuttering and occasional very short bursts of what feel like complete engine shut-down. This all is evident under light to moderate load .
At this point what would you recommend ? Replacing the O2 sensor bank #1 ? Or is there a possibility maybe the EGR valve is faulty - or another vacuum valve somewhere ? Intake manifold leak ?
The severe stumbling and very short complete engine shut downs would indicate that maybe the computer is failing or it's a fuel delivery issue? What rational steps to take next ?
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I have a 2003 Ford Focus ZTS with a ZTec 4-cylinder motor, 5-speed manual transmission, @145K miles (one owner). I had the fuel pump replaced in October 2012. For the past couple of months I have had intermittent engine surges when the car is under load, and it is most prevalent when undergoing heavy acceleration or when going uphill. The engine idles smoothly at about 800-1000 rpm. The problem seems most prevalent when I have more than 1/2 tank of fuel in the vehicle.
I have noticed that when the car is in cruise control mode and surges occur the accelerator pedal depresses as if the engine is trying to get more fuel. Spark plugs, Timing belt, tensioner, and water pump were changed approximately 30K miles ago. Alternator replaced @10K miles ago. No visible leaks around the head or valve covers. Vehicle is driven mostly highway miles in low dust environments. Engine light normally doesn't come on, but today the surges were worse than normal and the engine light came on several times over approximately 1 minute interval. Then the surges stopped and the engine light went out and did not come back on.
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