I have a 2002 Envoy XL with the in line 6. 118,000 miles. I was driving on the highway yesterday, and I felt it “buck” a little bit, and I lost a bit of power. It felt like I had a blowout. I pulled over, and the tires were OK. I went on, and while the RPMs were pretty much normal, I kept losing power. I pulled over again, decided to turn around and go home. I also stopped to check the transmission fluid, and I have plenty, and it’s clean (I replaced all fluids at 100,000 miles). As I pulled out onto the freeway, I had minimal power, but the RPMs were fine. I limped along, and eventually, everything was fine. I went along at 75 mph. I noticed that my idle RPM was up to 900, and it is usually 600. I never at any time heard anything which would indicate that something broke, like a “ping” or anything. Car seems to work fine now, but I also noticed that when I had the Air on the other day, it really seemed to suck the power from the engine. RPMS were again fine, but not quite the pickup I had before. Any ideas?
It sounds like it might be ‘driveablity’ problem i.e. a problem with the engine management system. Is the ‘check engine’ light ON or did it come ON? If so have the computer scanned. If the transmission shifts as usual; there is no slipping after any of the shifts; there is no harshness in the shifts; and the fluid is not burnt or overheated, the problem is probably not the transmission. The computer scan would probably also touch on transmission DTC as it believe the engine computer handles the transmission.
Good luck. Hope it was only a glitch or bad fuel.
Sounds like the engine computer problems that GM had in the eighties.
Have you ever changed your fuel filter?
Right off it sounds like a fuel problem to me, either stopped up fuel filter or bad gas with water in it.