My check engine light came on about two weeks ago on my 2000 lightning. so i plug up my tuner and it read running lean on bank 1 and 2. Just had it on the dyno about 4 months ago and the a/r was around 11.5 . The truck ran fine until i started to notice it was idleing a little rough in park and in drive at a stop light. Now if i get down on it, its starts to have a hesitation. I havn't done anything to my truck since the dyno. The only mods that i have done to my truck is change the 80maf to a 90, single blade accufab tb, cold air ram,upper and lower pully change( total of 15 lbs boost at wot ) tr6 plugs, borla ex. fuel filter and all four 02 sensor. I even check it for vacuum leaks and couldnt find any (2 cans of starer fuild). and went from sunoco gas to bp and no difference in change. Im stumped, does anybody have any clue what it could be? and also i do not have a custom tune on my truck. Thanks guys

 

Are you saying you have all them mods and NO tune?

Phil

 

All i have is a Diablo Predator to do the maf upgrade and the pulley swap. The guy at the performance shop only did two pulls and knock off two degrees of timing cause of spark knock. As far as i know he did'nt do any custom tune. the truck ran strong after that during the summer then the light came on about two weeks ago. sorry for the late reply, i just got home from work.

 

Sorry,,but I'm not sure ware to tell ya to start.
The guys on here can help you.
http://www.lightningrodder.com/forum/index.php?

Phil

 

I would change the fuel filter. Clean the mass air meter. You are going down the right track

 

plugs may have fouled out ??????

 

At that point, I would suspect a dirty and/or worn IAC valve.

 

Do you have an oiled air filter?
I had a similar problem that turned ou to be a dirty MAF.
My mechanic cleaned it, so I can't tell you how to do it.

Keep us posted...