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I have a 05 F150 4.6 liter with 107,000 miles.
I just replaced the alternator and that fixed my electrical problem but afterwards my truck was not running right. It dies at stops lights or when I slow down. When it does idle at stops, it isn't fluid. The RPMS bounce from 1500 to 500 as if I'm lightly pumping the accelerator. I changed the fuel filter 3 months ago. I just started doing my own minor maintanence so excuse me if the problem is obvious. Please help!
Thanks in advance for any advice!
I forgot to mention my check engine light is on.
Also, I found others on a different site with the same problem and they suggested to follow the procedures in the
owners manual under battery replacement. Disconnect the battery, start, let idle 10 min., turn on AC and let idle for a few more
minutes, then drive for about 10 mile. This is supposed to let the computer relearn proper idling.
Guess I will try this next.
Last edited by PITTF150; Jan 30, 2010 at 11:27 AM.
Reason: more info/update
The check engine light means that you have codes. Take it to someone that has a reader and have them read. Some of the automotive parts stores will read them at no charge. Post the codes here some of the good folks will help talk you through the issues.
Damn the luck, I hopped in my truck to go to the auto parts store and the check engine light isn't on anymore. But of course the idle problem is still there.
The check engine light may no longer be lit, but there could be pending codes that will help you out. Not to mention that you may have the light lit by the time you get there.
Remove The plastic Air cleaner tub And open the throttle body Butter fly Look in behind With flash light If it is drity And it will be Remove throttle body the And clean with some degreaser 4 bolts and two elec plugs be care full with gasket if not damged reuse worked for me
I went ahead and bought a code reader but there were 0 diagnostic codes and too many pending codes to determine anything. I'll check out the throttle body. Thanks for all of the suggestions.
CEl came back on so hooked up the code reader and got a P0506 Idle Control System-Low RPM. Base on my research I'm thinking it is the idle air control valve.
Check to be sure you don't have a vacuum leak in the hose running from the PCV valve to the intake. They are notorious for deteriorating and the up/down idle sounds liek a vacuum leak to me.
Last night I decided to clean the throttle body and clean the MAF sensor at the same time. This morning on the way to work, truck idled great! It's very rewarding fixing your own truck, not to mention less expensive. I just started changing my own oil a few months ago.