Ford F-150 - 1997-2003 :: RPMs Drop / Surges Over Bumps Only - CEL Flashes On
Jan 19, 2013
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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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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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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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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My 1999 5.4l runs great then after driving about 20 minutes, surges & stalls if you try to accelerate. Then the idle surges from 600 to 1500 (back and forth). Connected a fuel pressure gauge, and it shows 30 then drops to near 0 then bounces back to 30 then near 0, then back to 30 etc. No codes are reporting. What to check? Let it cool down, process repeats. Has new fuel pump & filter.
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03 supercrew 5.4. I've been having problems climbing hills. I'm on a trip and the truck surged fron do then to drive and stopped. Let it sit for 30 mins or so and it was good. Drove another 500 miles ans started again going up some hills. The first time it was 110 out and the 2nd it was 90. I'm pretty sure it's a cop but of course no cel. It does not seem to of over heated either. Can the cops overheat? Do you recommend a diagnostic, will this show up if no cel has show?
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For example. If you are going 30 mph the engine surges. It surges when the throttle is in the same tps location.
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I have a 1997 Saturn SL1 with 100k. Every so often the RPMs will drop by 500-1000 or so for a second and then come back up to normal. This happens both when stopped at a light and while accelerating, and doesn't seem to happen predictably. I've already changed the filters and cleaned out the IAC, without any success. I've sprayed the obvious connection points in hopes of locating a potential vacuum leak, also without any luck. Other ways to locate a potential vacuum leak that wouldn't be overly time-intensive?
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2001 F150! It does this weird little surge, burping and farting away...but only in ambient heat. The engine never gets hot, it never over heats. What have we done? A full tuneup with new plugs and boots, oil change, new air filter, gas filter. It did it again...took it back in and had the fuel pressure checked, fuel injectors are fine...it can't be the fuel pump, it runs great unless it is hot weather. It has twice blown the P0171 system lean bank 1 code and has gone away after the tuneup and again after the new o2 sensor. It runs great, except in hot weather, starts surging and losing power...
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I am new to FTE and have a question about my 99 4.2l. After it warms up, i can shut it off and about 30 mins later try to start it again and it will idle very rough and sometimes stall. I also noticed that it surges sometimes with just off idle throttle when its cold. I am not getting any codes thrown, here's what I've done so far: cleaned the maf and throttle body, and it didnt work at all. I did convert my cht over to ect by using the plugged coolant outlet on the lower right side of the intake manifold and extending the connector wires which actually solved the problem a little bit but it still does it from time to time.
More info about the cht to ect conversion, but after reading that ford did away with them in later models i wanted to do the same while at the same time making it so much easier to swap it out if ever needed. No more getting under the truck. And where im at cht's are kind of hard to come by without having to order them Anyway, it worked flawlessly! I only had to extend the wires by about 8", wrapped them and ran it along side the injectors for a clean factory look. Ill try to post pics soon...
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'1999 F150, 5.4L, 85K miles ....
Fuel pump failed last year, had it replaced. Ran fine for a week or 2, then one day went into limp-home mode. Mech replace fuel pump relay, again ran fine for a month or so. Now when the ambient temp gets above 80F or so (yeah, it has already this year - I'm in Central TX), engine at full op temp, I'm experiencing some sort of heat-soak issue. Engine runs fine when cold, and at normal op temps on the road, but if it is parked for 15 - 20 minutes then restarted, the idle goes all funky - nearly dies, surges, etc. for a minute or 2, and then it seems ok.
I would go back to the same mech, but he had to close his shop due to health issues, so I'd like to see if I can resolve this. So, it is definitely heat-triggered, and "seems" like a fuel issue, but of course it could be some electrical contact having difficulty above a certain temp.
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Have a 2003 F-250 with 174,000 miles. Recently replaced CPS and ICP and it's running much better. It normally idles at about 700 rpm. Lately, after driving for any distance above ~40mph, when I come to a stop, the rpm won't drop below about 850 rpm. If I shift to neutral (automatic trans), the idle drops to around 700. At the next stop sign/light, it's back up to around 850.
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I have a 1997 Audi A4 that has been acting a little bit strange lately. When it is started up and left to idle all of a sudden the RPMs drop from around 600-800 to 100-200 sometimes rebounding back up and sometimes the car just dies. This also is happening while I am driving and stopped at a stop light for a short time. It will idle fine then suddenly drop RPMs and if I don't give it any gas then the car usually dies. I have just had some work done on it to try and fix this problem thinking it was the air flow sensor (or something like that) but apparently that is not the case.
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My '03 7.3 is "surging" on idle. When warmed up, and idling, the RPMs will drop by 300 or 400 for a few seconds and then will correct and shoot back up. It cycles like this (every 5 seconds-ish) continually . I just put in a new IDM and checked the UVCH - is there a separate idle control mechanism that I need to have a look at? (2003, 7.3, 214K, stock).
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the wife's '01 Excursion has developed a new idling quirk. While sitting, it will briefly drop rpm's. You can hear it, and see it on the tach gauge. No other noises or problems, except for the brief drop in rpm's.
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2003 7.3 excursion.. The truck starts every time revs up and idles about 3 seconds then the rpms drop and it tries to stall out catches itself then revs backup and idles rough similar to if you have got air in the fuel lines from changing the fuel filter.. About 1 in five times the truck will stall out and it starts and immediately and idles rough but the rpms and everything runs at speed and rpms don't drop again! This is a reman engine/transmission recently installed.. The mechanic who installed it was unable to figure the problem out.
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I ran out and test drove a new to me 2001 F350 7.3L tonight. Everything seemed good, until I got back from the test drive. I pulled in and was sitting there with it idling. It seemed to idle fine, then a very small miss and very small shimmy then idle fine again; then another small miss and another shimmy. It continued like clockwork. Every time it seemed to miss and shimmy, the RPM would drop just a little, but not much. Does an ICP sensor sound like the problem, or maybe something more serious? 2001 F350 7.3L with 235,733 miles new trans, turbo replaced at 150,000 something miles. No blow by. Idled fine before driving, also drove fine. It doesn't seem to surge when idling, just kind stalls and shimmys for a split second then idles fine for a few seconds.
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I have a 2001 F150 4.2 V6. Three days ago, I noticed the Theft light blinking while driving. At first, there was no issues with performance, although the blinking was most noticeable just as I tapped the accelerator at cruising speed.
I thought it may temporarily disconnect the battery, which I did. After hooking it back up, I went for a test drive. About five miles into the drive I picked up an intermittent, though somewhat steady skip--almost like a plug wire. Shortly thereafter, the flashing light returned.
I'm not sure if the two problems are connected (the light and skip) or if it's just a coincidence.
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Recently I have noticed that when on a tune other than stock I am getting a surge at idle - my RPMs drop to around 621-630 then shoot back up to 660-675. On my stock tune my RPMs stay around 640-667 and don't cause the surge (felt as a shimmy so to speak). Is there anything else that causes a similar symptom? I attribute it to tuning due to it only happening when running anything but stock but could be wrong.
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2003 F150, 5.4 FX4, overdrive light flashes. Took to a shop they said overheating issue, but I don't understand if it is a overheating issue why does I flash at 4 in the morning when I leave for work fter sitting all night and why does it stop when I do over 70 on the highway.
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I have a 2000 f150 with 200k miles. I have no spark and no gas at the fuel rail Schrader valve. I have replaced the shaft pos sensor, no start. I have checked the fuses and the relays. I have crawled under truck and listen for the fuel pump to turn on while someone turned the key to on and heard nothing. I have 2 keys and while turning the key to on and start, the THEFT lite flashes. I have checked the impact sensor on the passing sick panel, it hasn't been tripped.
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