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BOBBYSS, Master Technician
Category: Chevy
Satisfied Customers: 17466
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2001 Chevy Suburban: sputters..runs is warmed up..plug wires

Customer Question

2001 Chevy Suburban idles rough and sputters when engine is cold in the morning, runs fine once car is warmed up. Already replaced plugs, plug wires, temp. control sensor - want to know what to look for next.
Submitted: 8 years ago.
Category: Chevy
Expert:  BOBBYSS replied 8 years ago.
HelloCustomer does it only idle rough or does it run poorly when you give it gas also when it is cold??
Customer: replied 8 years ago.
If you are sitting in park and give it gas, it doesn't get better. If you put it in gear and drive, it seems to run okay.
Expert:  BOBBYSS replied 8 years ago.
Okay. The most common cause of poor cold performance on this vehicle is an intake manifold gasket leak. It is common for this to leak until the engine warms up and the expansion seals it up. You need to check the intake manifold for and leaks. It may also be a dirty throttle body, but the engine will generally rev up fine when cold.
Customer: replied 8 years ago.
I forgot to add that the service engine check light has come on twice, but then has went off shortly after. The vehicle hasn't stored a code.
Expert:  BOBBYSS replied 8 years ago.
Okay. I really think you are looking at a bad intake gasket. Since it really does not cost anything though I would start by cleaning out the throttle body. It can cause a lot of cold idle related issues.
Customer: replied 8 years ago.
I already cleaned out the throttle body, it didn't seem to help. I used throttle body cleaner and followed the directions. In the morning when we start it up and it's running cold, it almost dies in between surging. You can hear the throttle body opening and the rush of gas or air going through, every few seconds you can hear it gasping.
Expert:  BOBBYSS replied 8 years ago.
If you havent checked the fuel pressure you may want to do that also. You may have a clogged fuel filter or a pump that is failing. Do you have a fuel pressure or a vacuum gauge?
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Customer: replied 8 years ago.
I will change the filter and look into the fuel pressure. Thanks
Expert:  BOBBYSS replied 8 years ago.
No problem. Let me know if you need more help.