OKay, Ive read alot of the forums and seen my problem alot. I just wanted to see if someone has figured something out. I had the same rough idle, bad gas mileage and so i changed all 4 o2 sensors. That fixed it .....For awhile. Recently When i put the truck in reverse, and then drive it, the RPM's will shoot down and up and go to normal idle. So far i've changed IAC, cleaned the MAF, checked for vaccum leaks, cleaned TB, checked PCV, changed O2 sensors. In other words i pretty much took the top of the engine apart and cleaned the MFer. It bucks like crazy and I worried i might end up hitting something. Any suggestions would be greatly appreciated.

 

Did you reset the computer after replacing the IAC?

 

yeah, and it fixed the problem for a short time but back to its "NORMAL" state.

 

maybe the TPS???????

 

I have a 2001 supercrew and have been fighting the same problem since I baught it used over 2 years ago. I replaced the o2's tryed 2 new idle air by pass valves new tps new delta pfe cleaned throtle body no change!!! it will be fine for days at a time and then drive you crazy every time you start after truck sets for 15 to 30 minutes. it starts fine then surges when put in gear I notice it to be worse with ac on. when the weather warmed up it was good for several days and then started all over. Once in a while it will not start hot I have to hold the trottle down a little and crank it then it will start and be fine. cold starts it is perfict and once it gets over this surge maybe a minute or two it is fine again to the next hot restart. I can't seem to help it at all. evrey time I change something and clear the computer it seems to be fine for a while and then the computer learns to do it all over, it seems as though it is just trying to be a PIA.

 

my exact problem. I think im done f'n with it for now. It doesnt affect the truck at all once it has warmed up, but maybe once a week after i start it and put it in gear the rpm's will shoot down. I changed the TPS on Saturday and seemed fine until Monday night when it did it again. I guess from now on i will just crank it and let it warm up for about 5 minutes. Cant hurt. If you do figure something out PLEASE let me know and i will do the same. Thanks

 

The only thing left to try is to clean the egr ports in the upper plenum, I don,t have any codes or check engine light no ping or any other problem. I do a lot of short local driving and this is anoying. Today it surged like crazy, I to am about ready to say UNCLE. I can't believe there isn't a fix for this. I checked for tsb's and have an auto tap and have been able to capture and datatlog an event but the parameters don't look abnormal. I think the problem is in the origanal computer program from ford.

 

My Mustang is doing the same thing right now but seems to be fine after it warms up. The tuner told me it was the IAC. I just haven't replaced it yet. Maybe you still have a problem with the IAC?
I just put a new clutch fan on my Mustang as well and it started to get on the hot side after 6-7 months. I discounted the fanclutch and looked elsewhere for the problem and finally ended up going with twin electric fans and problem solved. Point of the story is, I had a brand new Motorcraft police version heavy duty fan clutch get about 1,200 miles and the stock one got 106,000+ go figure? Sometimes just because you replace something doesn't mean that it's not defective. Just my two cents.

PS- I was told that the WDS at Ford is the way to go as far as troubleshooting goes. It's a realtime scanner and can tell you just about anything concerning your truck. Injector flow rates, spark, cylinder problems, etc. My dealer wants $175.00 to perform the test.

Good luck, Sean

 

I took the entire throttle body off last nite(2 A.M) and a huge buildup of carbon in the ports. It took me about and hour, 2 cans of CARB cleaner, 200 Q tips, 1 toothbrush, and 1 pissed off woman. All is well for now, no surging (1 day so far). I read another post about this guy's idle bouncing between 5-6, when idling and he ended up changing spark plugs and coil and it fixed his problem. No surging mentioned though? Mine does have a slight bounce to it, barely noticeable. I didnt take the EGR off but i cleaned what I could. So far so good. I'll stay updated.

 

I have a Ford 5.0 Multi port fuel injected motor in my Boat and it does the same damn thing. It starts okay when cold, then starts to have a loping idle after about 30 seconds. It will do this unless I give it throttle in neutral, at about 1200 rpm's it runs smooth. IF I let it warm up for about 10 minutes like this, it will idle somewhat ok, but still surges.

When I try to start the engine while it's hot, it will not start unless I have the throttle depressed, even then it takes about 30 seconds of cranking for it to run on its own. I thought EFI motors are supposed to run smoothly right when you start them, but not this one. I had the IAC Solenoid changed out last year, and it did nothing.

Seems like a problem with the FORD MFI Engines.

 

it's been 3 days and still good. i give another 2 days before it %&@! up. i'll keep updated.

 

Did you disconect the battery or clear the computer when you did this???? I'm keeping my fingers crossed I shure hope this fixes the problem, please keep us informed. I think I am going to order the gaskets and check mine I guess with 60,000 mile there has to be a fair amount of crud any way.

 

yeah, i disconnect the battery when i change sensors and etc. (if I remember). I had alot of crud in mine, but it seems to run alot better and i got some hp back. Feels nice to have a powerful truck again. Good luck on yours and keep me updated.

Chris

 

still good but im still worried. I drive a 2001 f150 4.6 at work 3 days a week and i notice that it has alot more power than mine. Granted, it has 15,000 miles less on it. I still feel like mine is lacking it's normal power. I think im gonna changed spark plugs and wires within next week. Oh yeah, my Cruise control went out today so i'll be up at the ford stealership to hear a load of BS about my extra care warranty, and why it wont cover it.

 

change spark plugs NOT WIRES (kinda hard to change plug wires if i dont have them)