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Topic
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Help!!!
I’m having problems with high idle in my truck and I’m due for an emissions check soon.
So ever since I’ve owned this truck its had rev issues. Its a manual transmission, between shifts while the clutch is engaged the revs reach about 3 thousand, this used to occur then go away in a couple minutes and not come again for weeks. not it does it every single time no matter what. In addition, now when I sit at a stop light the engine runs at about 4 thousand rpm, its gotten so bad that I turn my truck off at stop lights shifts hit really hard now because the engine is racing and grabs the clutch as soon as I release it.
If I unplug the IAC valve it all completely goes away and is fine, idle is a little low but not too bad. However this throws another CLE code and I have to echeck before november so i need to clear this up. I replaced the IAC and it still doesnt work if anything the new one is worse. I am also getting engine lean codes and knock detection codes. I did a smoke test and found nothing. im gonna try cleaning the MAF sensor. Any suggestions?
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Hi and welcome to the ETCG forum!
Hopefully we can get you some help with your problem.
Some information like the Make, Model, Engine, and transmission on your truck would be very helpful to us. As well as any modifications you have made and possibly what state you are in for emissions check.
2002 ford ranger edge with 5 speed manual and 4wd 200,000mi
only mod is a replacement muffler but its nothing serious no modifications to the rest of the exhaust system
High idle and lean condition are textbook symptoms of a vacuum leak. If equipped with a MAF, it could also be MAF related.
Karl
I smoke tested it and found two vacuum leaks, fixed them. And cleaned the MAF. Still doing it. Why would unplugging the IAC correct it.
Idle air control valve lets air past the throttle to increase engine speed. If you already have a vacuum leak, that’s also letting air past the throttle and into the engine, increasing engine speed. Stopping the IAC, or the leak will lower rpm at idle.
Check for leaks in the evap system too. Might have missed a stuck vent solenoid during the smoke test. You can also use a vacuum pump or blow through the lines to test solenoids, see if they open or close.
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