Hi there. My 01 UL has been sputtering in the morning when I come to a stop. It feels like the car is going to stall. I can press the gas and the car accelerates like normal with no issues. I have cleaned the throttle body, MAF and lots of other things to the car. Any ideas? The car runs great and I am crossing 100k miles today

 

Any MIL code(s)? Did the sputtering start after you cleaned the throttle body? It's also possible the OCVs are going bad. Easy DIY if it's that.

 

I cleaned the throttle body probably 600 miles ago with no problems. No codes or lights. What is the OCV?

 

Maybe a bad engine temp sensor. Only happens when the engine is cold?

 

Oil control valves (solenoids). The solenoid controls the variable engine valve timing. There is a thread here about it. But you would (should) have MIL code(s) P1354 and / or P1349.

 

Yes. There is a stop sign a few blocks from my house and the engine is cold.

 

My LS would randomly stall out when I came to a stop. I then would be unable to start it for a while, then it would run fine. No codes/check engine light.

It ended up being the fuel pump that was on its way out. No problems since replacement.

But I would do more diagnosis though before just throwing a fuel pump at it.

 

If you are going to drive any extended highway miles, I'd try running a proven fuel injector cleaner through the gas just to make sure that your prior throttle body cleaning hasn't clogged the fuel injectors at low RPMs.

 

Agree - try a large bottle of Techron (the concentrate not the diluted cheaper version) for a couple of consecutive tanks of gas and see if it helps.

Also check to see if coolant temp is coming up normally in case you have have a stuck thermostat although wound not have much effect in Tx.

 

Thank you. I put in a bottle of techron today. Hopefully that will help!

 

The fact that it only happens when your car is cold make me thing that is most likely is not injector or induction related. What is your idle like when the car is cold? And again, once the car is warmed up it does not happen at all?

 

Idle is fine when cold. I let it warm up today and didn't notice it weird.

 

Idle is higher RPMs when cold, so that could overcome a clogged injector.

 

Here are some questions that come to mind...

• Does this "sputtering/stalling" only happen in the morning?
• When it happens, does the RPM stay low, or does it "hunt" (cycles up and down)?
• Does RPM return to normal once the engine is up to temperature?
• Have you tried leaving the A/C off in the morning to see if it makes any difference?
• Have you checked the air filter to ensure sufficient flow?
• Have you checked your PCV and hose?

 

Ok so I got an MIL light today and the code is p1354. I cleared to the code and am gonna keep an eye on this. The car hasnt been stuttering at all this week. Weird.