Has anybody had the following problem with their F-150 idling too fast. When I come to a stop, the engine will idle too fast for about 4-5 seconds and then idle back down. This is the fifth time this has happened to my truck. Currently I have 70,000 miles. I have taken it back to the dealership for repair each time. The last repair at 35000 miles, the throttle body was replaced about 1 1/2 year ago. Now I have having the same idle issue again. This tends to happen when the outside temp. is warm. Now my "Check Engine Soon" light is on. The manual states this is a sensor problem. Would the throttle body be the cause? Is this a common problem with other 2003 F-150 truck owners? Thanks for any information.

 

Yeah im actually have the same problem right now! i have a 2003 ford f-150 STX regular cab and i put a airaid intake system on and a throttle body spacer and my check engine soon light came on and never went off and so i took all of it off and the light is still on! my truck wont even pass inspection i dont know whats wrong! Now my truck starts idling when it sits in park for a couple of minutes and when i start my truck it does it sometimes! If anyone knows anything about these problems please help me!

Thanks

 

Your IAC (Idle Air Control valve) may be stuck because of carbon deposits. It's basically a solenoid that opens and closes that controls airflow through the throttlebody at idle. It sits directly on top of your throttlebody . It'll have a wire going to it. Disconnect it, unbolt the IAC valve and clean it out really good with Throttle body or carburetor cleaner. Work the plunger back and forth "slowly" to make sure it works properly. Then put it back on. If it helps it, I recommend replacing it to prevent future failure.

Another thing could be your pcv valve needs replacing. As this too will effect the idle quality of your engine. It is located on the passenger's side valve cover way back in the back. It's a bugger to get to.

Try that and see if it helps.

 

Almost forgot, you might try cleaning your MAF (Mass Air Flow sensor wires. Your MAF sensor is located on the inside of the filter box, in the half closest to the engine. Look real hard and you'll find two little teeny tiny wires about an 1/8th of an inch long running parallel with each other. Whatever you do don't touch them because they break easy! All you have to do is get a can of electrical contact parts cleaner and give them a few quick blasts. Then they're clean. What the MAF does is, it controls the A/F "Air to Fuel" ratio by sensing how much airflow is going past the maf wires at any given throttle position, and then tells the computer how much fuel to add to the mix. If the MAF wires get dirty, they can give false reading to the cpu (trucks computer) and cause a lean condition "as in more air than fuel". Which causes your engine to "surge" or idle at high rpm's. Hope I helped you out!

 

I have a 97 F-150, 4.2. When I installed an FIPK I immediately expeirienced the high idle problem. I have cleaned the IAC twice, cleaned the MAF, disconnected the battery, ran the engine at idle for 15 minutes half the time with the A/C on and then off to retrain the brain. The idle is better but not the same as before the FIPK. Why is the cold air intake affecting all these trucks. Too much air?

 

I noticed the same thing today. When I started my truck, the AC was on. It was sorta hot out, so I just left it on and went back to the garage to get something. And I noticed that my truck would idle high for two or three seconds, then go back to normal. Do you think the AC compressor kicking in is what's causing it? Also, I noticed my truck ran different when I had my K&N filter installed. It seemed to idle a little higher, and it pinged alot during acceleration. I put my old paper filter back on and no more pinging. I think these engines are very sensitive to any airflow changes. Maybe that's what's causing your truck to idle high is because the MAF senses more air due to the fipk, therefore the computer adjust timing to compensate for more air by adding more fuel to the fire, which causes your engine to surge. That may have something to do with the knock sensors too. Just an "edumacated" guess. Try putting your stock airbox and filter back on?