mrvedit

My daughter in Denver just bought a 2001 Suburban 6.0l with 165,000 miles. The truck is low on power and won't downshift going up a hill. She took it to a shop, not very familiar with LS engines, that took my advice to check TPS values (Ok), disconnected the MAF (made no difference), check fuel pressure (OK) and a few other checks. Replaced spark plugs.
Intermittently gives a MAF (P101) and EGR codes.

They did check compression and it was relatively low at 130, but consistent over all cylinders. Between the low truck compression and high altitude in Denver, is 130 reasonable or a red flag?

Does anyone have a recommendation for a reasonably priced, yet competent shop on the south side of Denver that can diagnose an LS1 problem?

Thanks.

mrvedit

FIXED. The problem turned out to be a completely clogged catalytic converter.