This car of my girlfriends has apparently be stuttering on acceleration for quite some time and I just found out after needing to drive it a few days. The car hesitates to downshift at any speed, hesitates to take off and gets 18 mpg city at an avg of 20mph. I took it to the Dealer to see if they could clean the fuel system after replacing spark plugs that were completely white even though they were only in there 40k miles or so and cleaned the throttle body(a notorious cobalt problem) by taking it off and doing my best to wipe it down with a rag and throttle body cleaner. The GM Top Engine Cleaner they used worked great for one tank of gas which also had seafoam in it, then upon the next fill up the very consistent and annoying misfires and hesitation under 2k rpms reappeared. Over 2k the hesitation is much less than what it was but still there sometimes. Im hesitant to take it back to the Dealer so I called Firestone. They said the complete cleaning will cost 140 dollars and I need to leave it there all day so they can really evaluate it. Could someone please tell me some specifics about their service to bring up if I decide to make that appointment and have it "fully cleaned" according to them and is it likely the carbon build up or something more? Any answers or advice are appreciated.
Also, on another note is Firestones gas tank fuel system cleaner better than say lucas oils or techron?
Thanks very much
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Has any actual testing been done as in checking live engine data on a professional scan tool? .. Fuel trims, TPS readings, 02 sensor data .. Misfire data?
Only at the Chevy dealer. P300 I think the code was and he said it was constant. I'm not sure the exact number of misfires in the test period but he did say it was way up there. There was also a check engine light that I had checked at AutoZone P0171-running lean. But other than that, that's all the information I was given about testing.
Cleaning services are great maintenance items, but sometimes hit or miss as far as fixing a hesitation issue because you just do not know how severe the damage is. Overall I would say BG Products and services are the best for these treatments though. Typically I would try the BG fuel services first as opposed to a costly repair like if the fuel injectors were clogged or leaky.
Only at the Chevy dealer. P300 I think the code was and he said it was constant. I'm not sure the exact number of misfires in the test period but he did say it was way up there. There was also a check engine light that I had checked at AutoZone P0171-running lean. But other than that, that's all the information I was given about testing.