My truck idles high at times, but not all the time, some times when im at a stop it will rev up to a max of 1100rpm, or when in park or neutral it will idle up to 2300rpm then after aprox 45seconds it drops to normal idle.... any ideas as to what mite be causing this? O2 sencor? TPS?


I have a 1999 F150, sport 4x4, w/ 4.6L V8, auto trans w/ shift kit, Edge Evolution tuner, airaid cold air intake, helix power tower, aurora 10mm plug wires, true dual exaust, detroit locker w/3.55gears (rear), drilled and sloted front/rear Big bear breaks

 

Clean IAC, MAF, check voltage on the TPS, clean carbon from TB/intake........

 

More likely the IAC cleaning it will getit to stop for a bit but in the end it will need to be replaced. Or you could just keep cleaning it. Take it off and spray it with electrical spray.

Good luck.

 

throttle plate sticking maybe - needs to bee cleaned up ..

 

okay so i am having this same problem and i know nothing bout any of this could someone maybe walk me through this... cause this is eatin my mileage away... i have a 99 f-150 with the 4.6 thanks

 

Hi;

I too am having this problem. Specifically, I threw a CEL, it's rich on the passenger bank p0175 I believe. Then about a month later on startup or even when going from D or R to Park, it would idle up way high, anywhere from 1200 to 2000 rpm. On start up, hot or cold it also idles up high.

The engine runs fine at highway or around town speeds.

It idles normally sometimes at 700 rpm, though. Doesn't matter if AC is on or not.

I've read through 15 pages of this forum and I'm getting pointed to IAC cleaning, TB cleaning and have read the DIY thread.

Any ideas beyond this. I'll do the work in the next week or so.

98, F-150 4x4, 4.6, stock engine.

 

well is there any directions or any books that could give me step by step of how to do this?

 

Theres This - http://www.fordf150.net/howto/throttlebodyclean.php

 

Well I figured out my fix for my high idle problem.

The fuel filter had never been changed over the life of the truck (i bought it used and the old records never indicated as much) so I did that this weekend and the truck idles smoothly now, I dont have a CEL on yet after resetting the puter, and it just runs smoother now.

FWIW, the fuel line clip tool is 5/16".

I poured out a half cup of muddy, rusty fuel out of the old filter complete with debris.....It looks just like rusty mud, 1/2 " thick.

So, I guess the high idle and p0175 were from the fuel being starved due to the clogged filter?

anyhow, as of now, it's fixed.


It's fixed....been a few weeks and several tanks of gas.