when i start my car it runs fine until it warms up or the high idle comes down. Thats when it starts to idle rough/sputter sometimes it will clear up if i rev it up alittle. It may clear up for 5 min or it might not clear up at all. Although when i drive the car it boosts fine and there doesn't seem to be any lose of power. Until i come to a stop light or where ever i have to let it idle is when it starts to run rough. It will also smooth out if i turn on the headlights.Things i'v replaced are plugs,coils,o2 sensor because there was an 02 code (cel),checked compression,mas,pcv,checked for vac leaks and checked egr valve for proper function and to make sure there was no carbon build up. Also the engine code that comes up is po300 random/multiple cylinder missfire. When i turn the lights on you can hear the fuel pump change pitch for a sec then it smooths out.(255lph). mabye the pump isn't working correctly. Any help or suggestions would be appreciated. Thanks.

 

anyone?

 

Do you have a wideband? Check your afr's. It could be a vacuum leak or a boost leak, double check ur connections there.

 

no wideband just one of the cheaper autometer gauges. If i had a boost leak wouldn't i notice it when boosting or I wouldn't get full boost(RRM stage 1).Thanks though, im going to look over everything again for the 100th time, the car actually stalled about a month ago and i couldn't get it started till the next morning,which is the same time the idle prob started.

 

oooh, the headlight thing. clean your throttlebody.

 

what would cleaning the throttle body do? What would i use to clean it? Thanks for the help.

 

i didn't have any throttlebody cleaner on me so i just used a rag. there is a default gap between the throttle plate and the throttlebody inlet. if it gets clogged, there will be problems with the car dying as the minimal amount of air to keep the engine running has been cut off.

if you get a can of throttlebody cleaner, don't forget to block off the Idle Air Control valve openings as the spray could do damage to it. the spray also cleans off deposits in the intake manifold as well.

 

thanks. Ill try today. Also when the car starts to idle rough the vac on the boost gauge starts to rise alittle from 20 to 15. i'v checked so many times for any vac leaks and to make sure all my intercooler pipes arn't leaking but mabye i should check again? i think the vac is just changing due to the flucuation in idle. Or mabye my bov isn't func properly(greddy type rs) mabye ill try putting the stock one back on that came with the kit and see if it makes a difference.

 

It really could be a bov

 

can you explain that a bit more, what is the Idle Air Control valve?
i cleaned out my throttle body the other day and i just sprayed it inside there while openig and closing the throttle.

 

there's a hole right in front of the throttle plate. you're not supposed to get any spray in there. i guess it's too late

 

lol i guess so. i havent noticed any adverse effects so i think im ok