Too lean would be a tuning issue,low fuel pressure or a vacuum line disconnected.

It needs to be scanned.

 

Your ltrims are probably +25, if so, you have a vacuum leak.

good luck,
allen

 

i cant here any knocking or pinging. but im taking it easy. havent really driven it much latetly. what are the best places to check for a vacuum leak? right at the manifold? maybe a bad gasket? also fuel pressure is good.

 

I would agree that you either have a vacuum leak or a problem at the fuel pressure regulator (which is in the tank). I would assume your problem came about when the fuel pump was installed.

 

Try finding a shop that has a smoke machine, they'll pump smoke into the engine and where ever the smoke comes out...

good luck,
allen

 

depending on who did the install, it is more than likely an install issue. I would start checking your install and backtrack through everything.

 

Did you figure it out?

 

still havent figured it out. ive been away from my truck for a few weeks. ill be checking it out on wednesday. i called the shop that did the install and they said to check for a vacuum leak if i can then bring it in. when checking for a vacuum leak do it yourself style, whats the best way? carb cleaner? where all should i look? just around the manifold or anywhere else? thanks alot.

 

Ether spray. Anywhere after the MAF that air could be getting in. The manifold to heads is a likely suspect. Could have cut the gaskets during install. Only do a few minutes at a time then let the truck cool. Maybe its just me but I don't like spraying flammable things on a hot engine.

 

I had a similiar issue. It turned out to be a combo of bad fpr gasket and stock plugs were way to hot. I believe they were replaced with ngk tr6 I think. I can check if you want.