1999 Automatic, 156K Only mods are 4" exhaust, K&N air filter and rebuilt tranny. Lift pump pressure is fine, fuel filter has been changed, truck idles really bad rough. Once you put the truck in gear it smooths out, drives fine no power loss of fuel economy loss. No codes found, I have killed each injector using a test feature on scanner every time you kill one injector the idle definalty gets worse. I am lost please give me some advice. Under a idle or deceleration mode is the only time you notice the Miss.

Thanks David

 

I have been dealing with the same thing for a year It slowly gets worse sorry to say I tried all the easy stuff , APP reset , IAT. MAP. new injectors. just ordered a new Vp44 $1100 bucks . low pressure at idle will not pop off the injectors is the cause.

 

Check the EPS

 

New VP44 pump fixed it! started right up no more miss,less smoke. idles at 825 now.I will see if I get my fuel mileage back with the new pump!old pump made it 82.000 miles.