2003 Chevy Suburban missing/lunging at idle/intermittent en

Tiny
TEMPIE
  • MEMBER
  • 2003 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 125,000 MILES
Runs good on highway but rocks while idle. Replaced number 7 injector, fuel pump and manifold gaskets with tune up and fuel cleaner all done at dealership. Over $1000 and still runs rough. Mechanic friend says sounds still like vacuum problem . Where would the problem be or is it something else? (What runs off #7 vacuum. He also sugguested if something was going bad it could could the problems.
Thanks
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Monday, February 18th, 2008 AT 11:11 PM

4 Replies

Tiny
PEAR69
  • MEMBER
Why did you replace the 7 injector? There sounds like there is more to this story. Try to remember everything. Is there a check engine light on?What octane fuel do you use?
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Monday, February 18th, 2008 AT 11:37 PM
Tiny
TEMPIE
  • MEMBER
My car was rocking back and forth like it was missing when it was idling. Sometimes the check engine light would come on. When it stayed on I took it to the dealership. They said #7 injector was bad and cleaned the manifold, changed wires and plugs and cleaned all other injectors and ran fuel line cleaner.
When I left my brakes felt mushy and it ran okay for just a little while. I took it back and they said computer showed that #7 injector was bad and they thought they had gotten a bad one installed and replaced it immediately. It was still missing but they said they couldn't find anything wrong. There was no longer a engine light on but agreed that it was running rough. Again the brakes felt mushing but seemed to get okay after I drove it a while. Later, I Took it to another dealership. They replaced the fuel pump. (Which is the 6th fuel pump this vehicle has had and they did it under warranty). They were just making guesses about what was wrong and wanted to do a valve job but other dealership said there was nothing wrong with valves or lifters. I got tired of the dealership and took it to an independent. He replaced the manifold gaskets and it ran fine until they let it set for a couple of hours. The vehicle has always run fine at highway speeds and usually if there has been a check engine light on it would go off. The harder you get on the accelerator the better it runs. The independent guy said it looked like the spring(s) in #7 looked new. I always use regualr unleaded octane.I never check the number. I am a female who knows nothing about a vehicle except what I am told. I don't want to be taken.I don't want a new vehicle and I don't want to be stranded. I hope you can help.
Thanks.
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Tuesday, February 19th, 2008 AT 11:03 AM
Tiny
PEAR69
  • MEMBER
It is very difficult to diagnosis your problem because almost all of these engines have the same problem but they all have a different problem. My question would be to the dealership that changed the #7 injector twice. I would ask them what lead them to believe that it was #7 injector? If they say that the computer showed a code or their engine scanner told them so (or something like that) ask them what the DTC code number was? DTC means Diagnostic Trouble Code. A DTC will turn ON your check engine light. When this happens there is a sensor somewhere on your vehical sending a trouble code to the computer. These codes can be read by a scanner that hooks up to a data connector located within 3 feet your steering wheel. If you look under the dash below the steering wheel, just a little to the left you will see this connector.
These codes will lead you to the area where the problem is coming from. Without having the DTC code that your engine is setting off It is very difficult to tell you what is wrong.
The good news is that Autozone or a place like that will scan your engine for free and tell you what code is being set. So the next time the check engine light comes on go to Autozone and have them hook up their scan tool and get the trouble code. Let me know what it is and I will have a better answer to this problem.
The dealer that changed the #7 injector should have a record of the code they got that lead them to change the #7 injector twice. If not then I would say that you have been taken advantage of. This type of stuff realy gets under my skin because computers in cars are intended to make problems like yours easier to diagnosis and fix.

BTW- You can buy an inexpensive scan tool at Sears or any autoparts store for your vehical. For you this may be a good investment because then you could scan your own engine and have an edge on a shadey mechanic who may fix something that wasn't even the problem.
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Tuesday, February 19th, 2008 AT 2:34 PM
Tiny
PEAR69
  • MEMBER
One more thing, don't let mechanics change things unless they prove to you that the part that they are changing is defective of bad. Anyone can change all your sensors and stuff and sure it will fix the problem but you will end up with a bill that will remind you of the National Debt.
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Tuesday, February 19th, 2008 AT 2:38 PM

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