Looking for Help with rough idle and p0301 p0302 p0303 20B0 codes

[BG2005GT25]

The engine and turbo were rebuilt about 3000 miles ago. Was running ok now runs great no idle issues or codes when motor is cold. Once it warms up idle is rough at stop signs and will stall at times. If it stalls it will produce p0301, p0302, p0303, 20B0 codes. It also had a lean issue from air leaks past MAF. I replaced the turbo inlet tube the end that attached to the turbo had a big tear, the lean code is gone but still have issue with the others. I am at a loss is this a crank sensor, pcv, egr, or something else. Where should I move to next. Thanks

[KZJonny]

If you have had past issues with boost/vacuum leaks, I would start with a smoke/pressure test of the whole intake. From your tag, I assume you've got a MY05, so you'll have the infamous 'blue tee' somewhere under the intake, not to mention unless you've already done it, about a mile of 20 year old rubber hoses in there. Lots of potential points of failure.

Also, cleaning the MAF sensor itself as well as the connection might be a thing to do. Wiring in the harness going to it is another known failure point. Other have been able to cure/cause similar codes just by moving the wires around while idling. Could be a simple test to see if yours in on the way out, or in need of some TLC.

[BG2005GT25]

Thanks, was going to do a smoke test this week (hopefully tonight). I cleaned MAF sensor with CRC electrical cleaner but did not look at connect will do that. Yes, miles of old hoses really hoping it's not them. I am going to remove the intercooler and clean the pcv valve. Is there an egr valve i can't seem to find it but read in one post that the turbo model did not have one. 

[BG2005GT25]

one other thing it does seem to get hot not screaming hot but up there. when the thermostat opens it drops down but i wonder if it is running lean.

[KZJonny]

No egr, no! Thankfully.

MY07 forward got a secondary air pump system to increase the cat temperatures and get the emissions down faster. Many delete it.

Do you have a way of looking at fuel trims?

I do not have one, since I am on a COBB AP, but BTSSM is meant to be very good, and a low dollar investment.

Lean on these engines is a bad place to be, so maybe get on that smoke test pronto?

[BG2005GT25]

I can see live data i will check to see if can see the fuel trim what is an acceptable range thanks

[KZJonny]

Better question for the "tune their own car" crowd, but I want to say that inside 5% is acceptable, generally. Closer to zero is better.

 

I am pretty sure that positive trim is adding more fuel, trying to correct for lean conditions, so in your case, that would be the indicator... If you suspect running lean.

Of course, there are the obvious checks to perform like the state of your radiator and the age/condition of the coolant. Those are obviously going to be pretty significant factors.  A rad flush and new coolant is cheap insurance; new main rad hoses as well, if the ones you have are of unknown age, or questionable condition.

Edited November 29, 2023 by KZJonny

[silverton]

5 is good, 10 is okay, 15 there's an issue, 20+ fix that shit before you break it.

[BG2005GT25]

Thanks for the information I didn't get the smoke test completed last night; wife had other plans for me . The coolant is new when engine was rebuilt 3000 miles ago, but I think someone may have poured in some sort of magic sealant before me and I have had to flush the heater core to get temp issues resolved on the inside (also a blender door actuator). I agree it needs a complete flush and thermostat. I will post results of smoke test and live data.