Plz let me know what you guys think? Also what is an acceptable number for back pressure on the cat? It's a single cat and muffler...

 

P0141 1/2 02 Sens Relay

That is indeed the post cat sensor, but, it is whining about the relay. (which is for the heater circuit.) Don't recall if both sensors use the same relay, but, the heater not working would make the O2 sensor take a while to get up to temp, and actually start working right.

At idle, you shouldn't see any more than 2PSI in the exhaust before the cat. More than that, and it is at least partially plugged.

 

Does it run if you open the throttle a little bit?

 

Yes it runs if I open up the throttle but sorta takes half a second to catch on when raising RPM's, like something is holding her back. Like I said the usual behavior I get when it fires up is it will run up to temperature and slowly seems like it struggles to stay running, RPM's go from low 700's to high 500's and out of nowhere dies... Strange behavior???

 

I am gonna do a back pressure test for the cat and find out where I should be heading next. If it wasn't the cat what else could it be? I am running out of ideas, never had this type of problem with any of my cars or trucks.

 

To me it sounds like either the iac or the coolant temperature sensor..or loose connection at one of the two.

 

I was thinking maybe ECT but ain't too sure? Would you just check resistance for this? or voltage?

 

I doubt its the iac, it will still normally just surge or rough idle if its something iac related. coolant temp sensor could be a good idea though seeing as how ur sayin it shuts off at a certain temp.

 

When it's below 20f mine will only idle about 5-7 minutes (below 0f and I can get it started, almost 10) and then will die. Let it sit 5 and will run just fine...if I get in first thing, start and drive off it will sputter and buck (after a few miles) if I let off the gas for a good 15 miles or 20 miles....once it sits for a few it'll run just fine. Pretty sure my temp sensor is shot...coming out of the closed loop seems to be the killer.

Try that temp sensor if you haven't already...it's cheap. I'm just waiting on better weather and time to do mine.

 

I will do that, Thanks for the info guys. It really helps. ECT sensor is next.