O/T: '04 Trailblazer

[Anonymous-0]

My brother-in-law has a 2004 Trailblazer, 4.2, 4x4. It's "puttering and gutless(his wife's description). Also the Service Engine Soon light frequently comes on. They took it to 3 auto parts stores to get the codes. 2 stores said the computer was not responding. The 3rd store said there were no codes stored. Any ideas on this?

On the driver's side frame rail, there's a round, black plastic assembly. If I traced the two hoses back correctly, it's part of the emissions system. It has quite a whine/vibration to it. What exactly is this thing? Could it be part of the problem?

Opinions and suggestions are welcome. Thanks for your time. I've relied on you good folks many times, and always gotten helpful information. He can't afford $65/hr shop rates plus parts. Given that I know these late-model computerized vehicles are slightly out of my area of expertise as I don't wrench on a daily basis, this forum is an invaluable resource. Y'all are truly appreciated.

Thanks,
Anthony

 

[Anonymous-0]

If your going to own the newer vehicles, you had better get used to the shop rates. There is no way the average shade tree guy can do the computor stuff on cars and trucks these days. I have 4 trucks with computors on them. I have a guy that does on them what I can't for$45.00 to $50.00 an hour.
To start with your not going to have much gut in a vehicle that size in any case.

 

[Anonymous-0]

How much is he willing to spend at shops that can't fix the problem?