Poor performance

GritHead · August 23, 2006

I have a 2004 Silverado crew cab with a 5.3L engine which has been a DOG and I mean a D-O-G since the day I drove it home. I took it to the dealer who replaced both catalytic converters and all four O2 sensors. It may have made some improvement. Now here is the "kicker". In cold weather it runs pretty darn good but in 80+ degrees...a sick puppy. It has been back to the dealer who said nothing is wrong with it....because the analyzer says so. I traded in a 2001 Silverado extended cab that was a ROCKET! It was a great performer from day one.

I have installed a flomaster system and installed a K&N air filter to try to help performance with no noticeable improvement. The truck now has 20,000 miles on it.

Does anyone shed any light on this problem?

Nice rig · August 23, 2006

Didn't you test drive it before buying it???? If it's not pulling any codes then there is little you can do to find out what the problem is. Maybe try getting a tuned PCM.

GritHead · August 23, 2006

Didn't you test drive it before buying it???? If it's not pulling any codes then there is little you can do to find out what the problem is. Maybe try getting a tuned PCM.

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Yes I did a test drive but did not do any HEAVY acceleration. I was awed by the beautiful baby. Remember....this mostly occurs above 80 degrees F. I can spend $500 on a tuned PCM but should not have to. It should perform as well as the truck I had previously. No codes and the IAT sensor voltage is normal.

TEE · August 23, 2006

Try another dealer and have them check it.

95Sierra2500 · August 23, 2006

Didn't you test drive it before buying it???? If it's not pulling any codes then there is little you can do to find out what the problem is. Maybe try getting a tuned PCM.

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Yes I did a test drive but did not do any HEAVY acceleration. I was awed by the beautiful baby. Remember....this mostly occurs above 80 degrees F. I can spend $500 on a tuned PCM but should not have to. It should perform as well as the truck I had previously. No codes and the IAT sensor voltage is normal.

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It should perform as well as the truck you had previously, but not necessarily. Not all trucks are created equal, even if they roll off the same assembly line. It's the same way with most cars, too.

Rammer · August 23, 2006

Crew Cabs are heavier Than X Cabs by about 300 lbs and I'd bet that you have 3.42 gears in the CC and the XC had 3.73's. They will not perform the same.

jhm · August 24, 2006

Crew Cabs are heavier Than X Cabs by about 300 lbs and I'd bet that you have 3.42 gears in the CC and the XC had 3.73's. They will not perform the same.

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The temperature (ambient) seems to be the key to his problem. All engines run better when the air is cool (dense), but the way he describes the difference, runs like a sick dog, I would bring it to a different dealer and see if they can trace the problem.