I've been working on this truck for weeks. Latest codes p0172. P0174 lean on one bank rich on the other fuel trims are good only when I shut it off and turn back on stays good for 30 sec then go out of whack. I have no cat. It was removed before I got it. If I replace the cat would it help on the fuel trims ?

All hoses been replaced along with o2s both upstream. . Iac. Tps cps. PVC valve
And fuel filter and pump also maf replaced.

I sprayed the intake. Can't find a leak

Can anyone think what else could cause the. The problem Cats ? Pcm ? Any of the egr stuff

Fuel pressure is 35- 45

 

bump it for you. Hope that someone has some ideas.

 

It sure sounds like you have a vacuum leak.

 

Lean side or rich side.? I can't find a thing. The only thing I can think of would be the Evap cansiter purge valve. Faulty as that has vacume from the intake. Evan thou I have all new hoses could be leaking from the inside.
I don't have a vacuum gage but I guess it's time for one. Or rent one.

Didn't think it would be that. Because of one side rich other lean. I could see it if it was a po171 and po174. Both lean

 

Lean side. The PCM is trying to compensate for too much air by throwing more fuel at the engine, which is causing the other bank to go rich.

 

Is the truck missing ? Have you reset KAM ? Do you have live data ?

 

No misfires Reset the kam from my meter Reset the pcm. I do have live data

 

I'm going to go rent auto zones vacume tester tomm. See what I can find. Just at a loss.

 

Use propane and a small hose . Watch short term fuel trims while searching for a vac leak .

 

Ok I'll try that I have a tank have to find a valve don't want to cut my grill. Lol. Or could I use a propane torch ? Un lit of course. Could stick a hose on thar for a few bucks.

 

I use an UNLIT torch and a length of hose . Good luck Graph the data pid if you can . Better than trying to watch some bouncing numbers .

 

Well at least I have some stuff to try. Thanks. Send any other things I can try. I'll do the vacuum tester first and check a few sensors that could leak internally if bad then I'll move on to propane .

 

I'll take my ipad and do a video. And send it your way tomm. By email if you can pm me your email. Thanks !!

 

Jwc. What do you want me to graph. Short trim. Long trim ? I think I can fit 4. On the screen

 

While looking for vac leaks , graph short term . If you graph long term, while driving , you can see what the ecm wants at different load cells . Tack on a graph of maf and tps while driving and you can get a lot of useful info . That is , If you know what to look for .