Need help. Erratic idle. About a month ago, when coming to a complete stop, the engine RPM's jumped to aprox. 1100 causing the truck to learch forward (almost into the back of the car ahead). This would happen occasionally. I replaced the IAC, MAS removed and cleaned the throttlebody, intake runner, EGR, PCV. This problem has not returned. The next problem has existed prior to the erratic idle and has both of the Ford Dealerships puzzled. They want me to drive the truck until something breaks. One of the dealers thinks the converter clutch is not releasing (even though the high rpm happens in PARK). Their are no error codes. When coming to a stop from average driving, the RPM seems very high (850-1100). This causes the truck to continue to pull for a few seconds, then the idle slows to normal (580-600) and all is well. If I put the trans in neutral while the truck is pulling at idle the RPM's jump to about 1100 for a few seconds. This happens more frequently after the engine temp is at normal and the outside temp is above 90. Have noticed when at idle (for 15-25 minutes) in park the engine idle creeps up to between 900-1000rpm's. It will continue to idle high until I drive for a few blocks, then the idle returns to normal. Generally the truck drives and shifts normally, gas mileage is still about 16 in town with air and 23 on the road with cruise. Can not find any vacuum leak, or air leak in the intake system. If I set the cruise control to 30 MPH the truck will not maintain a level speed, it increases and decreases speed to the point where the cruise turns itself off. I can not maintain a steady speed with the accelerator on level ground. If cruise is on and going down a hill the vehicle speed continues to increase to where I have to brake to keep from running over someone. Have had very little trouble with the truck, engine oil changes at 6K, trans flush at 20K. The truck has 62k and always starts and runs all day long. No hesitation, always has power when needed. This is a service vehicle at work and makes 8-10 service calls a day.
Any help work be greatly appreciated.

 

I too have 2001 supercrew that has strange idle problems. When i start it in warm weather with a mid to normal operating temp it will start idle fast annd return to normal if i have the air on the idle will surge from 500 to 1500 rpms if you hold the throttle down to make it idle for app 30 seconds it will be fine if you dont iy will cary on to it stalls. Sometimes without air on it will start and idle and then when put into gear it will take off you better be ready with the brake or else. Once it settles down it is fine untill the next time the truck sets for 30 to 40 minutes. I also had tried two new iac's new mass air flow cleaned throttle body and also checked vac leaks. I might try a tps never has any codes had dealer check for service bullitns. I wander if it is acomputer program error my truck is a 4.6 with a computer code of wiz2 what engine and code do you have? code can be found on passenger door opening in front of door or you can look up at the computer from the passenger side above the plastic kivk pad. This is the only problem this truck has it drives me nuts, and I dont have far to go.

 

It does seem that we both have a common problem. Mine seems to act up after the outside temp goes above 90 degrees. In the mornings the choke circuitry seems to function normalls, releases from fast idle after 3-4 minutes. I have posted this message on several other boards and this is the first reply with someone else with the same problem. I did have the dealer use there scan tool to check for errors or a snap-shot of the system when it malfunctions. But as luck has it they leave the truck sit in their driveway or behind the building until it cools and they can't find the problem. I purchased a recording scan tool in hopes of seeing the problem first hand, but since the last article the temp here has not jumped above the 90 degree mark and the truck has been running fine.
One other item that seems to happen, when the truck has its problem the power of the engine seems to be way down. If I hold the service brake and floor the gas it will not turn the back tires.
The only other thing that I can think of, as being changed, was back in April I had a shorted COP and the plug and coil were replaced. At this time the dealer said that the firmware in the computer was out-dated and needed to be upgraded. The only thing that I noticed that my MPG dropped about 2mpg because of the upgrade.
If have any further info please keep in touch.


Thanks

 

hate that you are having the same problem but am glad to here someone else is. I to have posted before but no one seemed to have the same problem. my power seems fine although I have a supertcharger and a troyer custom tune this truck did this before when bone stock and is still the same. Mike says he changes nothing in the normal driving aspect only in open loop wide open throttle. I still think I am going to try a throttle position sensor. I have an auto scan and caught the thing while it was doing its thing the only yhing I saw was the idle air going allover the place , but thats what you would expect because its trying to atain the proper idle. IFi find anything out I will post, please do the same. thanks Chuck

 

I do not know if newer fords increase the idle when the computer senses that the coolant temperature is too high. Older fords used to do this. If the truck is heating up or if the computer senses that it is, (because of a defective sensor), it may cause the increased idle. Maybe someone can confirm this. Hope it helps.