Hey guys. I've got a '05 4.6 with 120k on and just starting having some weird idle fluctuations. Like when the a/c is on and the compressor kicks in and out. But also just when I come to a stop it drops down to like 500 rpms and then back up to about 750. It almost acts like it wants to die. Besides that still running great. ????

 

do you have any kind of aftermarket tune in it? any codes?

 

Clean your MAF. K&N and other oiled filters can foul it, especially if you overoil it.

 

Negative on the aftermarket tune or codes. Whats a MAF?

 

MAF stands for Mass Air Flow it is a sensor in your intake tube between the throttle body and air filter box.

 

Could be that electronic throttle control isnt working right, I'd clean the MAF theres a how to somewhere do a search. Might try taking the throttle body off and cleaning it but be very careful not to damage the electronics in it use electrical parts cleaner on it and all..

 

OK, I cleaned the MAF, took off the throttle body and cleaned, sprayed throttle body cleaner into the plenum, changed fuel filter and cleaned the K&N air filter, and voila, that seems to have done the trick. However, the check engine light has come on. I think it came on because when i did the fuel pressure release procedure, the intake had a bunch of throttle body cleaner in it. It seems to be running fine, no more idle flucs, so far.

 

dont over oil the K&N.. That's what causes the MAF to get dirty. The rule is dont clean the K&N until its not showing purple anymore. They actually filter better when there a bit dirty. K&N says you can go 50k without cleaning it. I think they get over cleaned the types of people who buy them tend to be a bit ****..(*I have one). I'd have autozone pull the code just in case then reset the computer. Disconnect the battery for several minutes to do that.

 

I've been guilty of that for sure. Its funny you mention that cause I just noticed that it says 50 to 100k. And I have definitely over oiled it once for sure, but now i have the spray on oil and its alot easier to control. But I'm for sure gonna cut back on the cleaning. The good news is that the CEL self erased on Tue., and its really running good now. Thanks for the help!

 

funni thing i pulled into the parking lot and noticed it idle stable (RPM) on my truck but its has a bit of jitter..and it not constant it jitters like every 5-10 seconds..then normal...then jitter/slight shake again..i have a k&n drop in cud it be that ?

 

Clean your MAF..........

 

hey glc thanks after more research LOL ive been able to understand the concept, will do