hi, just looking for some direction as to where to look for a couple of problems. My truck, a 98 f150 with the 4.2L is pulling a trouble code, which is bank 1 & 2 running lean. Ive allready been playing with air flow sensor, wich dosnt seem to be the problem.

One thought I've had, could an exhaust leak ahead of the catalytic converter cause an O2 Censer to detect more oxygen than is actually thier, telling the motor its runing lean.



The other problem....one thats been annoying me for 3 years now. When its really cold outside (think -30 and colder) my truck runs like it has an old carburated moter with a stuck choke. It starts to have the problem at about -20, but below -30 No amount of warming up the motor will help. The truck just runs like crap untill its warmer outside.

 

I assume you have done all the testing for vacuum or intake leaks, don't forget to look at the vapor recovery system and the vacuum reservoir, also the PCV valve hoses.

 

thanks, hadnt though of checking vapor recovery system. Its a work in progress, I"ll try one thing, reset the touble code, and wait to see if it comes back on. then try something else. Trying to figure whats casuing it has been my pet project for a few weeks now



if you have a clue what might be casuing the cold weather trouble, I 'll try changing few things before it gets cold. I usually dont feel like working on the truck when its -30 outside. (no garage)

 

Was a report earlier about the ACT giving false info to PCM, in that case it was feeding a voltage representing -35 degrees. Would have thought it would have thrown a code, dealership had to fix that one. Something to consider.