I've chronicled my '02 Silverado engine problems on other threads. Got about 125k on it. I've had varying symptoms and problems such as hard starting, especially when wet. Then when I got that fixed, it started to run rough and missing. I'd be on the expressway doing 70 and all of a sudden it would bog down, start backfiring and I couldn't get above 45 mph even at WOT. First time it happened, I limped home and turned it off and after several test drives, restarting of engine it was still backfiring like crazy and no power. Then I checked the oil and was a little low, so I put about half a quart in, fired it up and it ran fine. WTH? That went away for awhile and it started again this summer. It got to the point I was afraid to take the truck on anything other than short trips I ended up replacing the Crank sensor, the cam sensor, TPS. Over the last year, I've changed plugs, wires, coil, rotor, distributor, MAF, FPR, Fuel pump, fuel filter, you name it. Had to take it to a shop after replacing the crank sensor for a reset. I can't believe all the massive problems I've had with this engine. It's a spare vehicle so I doubt I've put more than a couple thousand miles on it in the last year. It may sit for a week without being driven.
Anyway, its been running ok since summer after I replaced a bunch of stuff and then started running a little rough last week. Not real bad but wouldn't idle rock steady like it had been lately and a little hard to start. Then, on Saturday, it happened again. On the expressway at about 70 and it just starts bucking, misfiring, backfiring out of the blue and can't get above 45mph. Pulled over, checked the air filter (which is almost new). Took it out and tried again. Still couldn't get over 45. Pulled over again, checked the oil. It was a little low so I topped it off with about half a quart. Started it up and voila ran fine the rest of the way to my destination, no backfiring or anything. WTH? Heading for home after it sat for 3 hrs it started a little hard and was running rough until it warmed up and it was fine the rest of the way home (30 mile trip, mostly at 70 mph hiway). Got home and it would start but run rough at idle. Today, same thing and I put a scanner on it. The HO2 sensors are supposed to be between 200 & 800mv readings. Both Bank 1 & 2 # 1 sensors (before the CATs) are 30-50 mv while the #2 sensors (after the CATs) seem ok at around 190 &350.
The question I have is: does this mean my # 1 O2 sensors are probably bad? This isn't a tough fix and relatively cheap ($ 60 or so for the part).
Anyway, its been running ok since summer after I replaced a bunch of stuff and then started running a little rough last week. Not real bad but wouldn't idle rock steady like it had been lately and a little hard to start. Then, on Saturday, it happened again. On the expressway at about 70 and it just starts bucking, misfiring, backfiring out of the blue and can't get above 45mph. Pulled over, checked the air filter (which is almost new). Took it out and tried again. Still couldn't get over 45. Pulled over again, checked the oil. It was a little low so I topped it off with about half a quart. Started it up and voila ran fine the rest of the way to my destination, no backfiring or anything. WTH? Heading for home after it sat for 3 hrs it started a little hard and was running rough until it warmed up and it was fine the rest of the way home (30 mile trip, mostly at 70 mph hiway). Got home and it would start but run rough at idle. Today, same thing and I put a scanner on it. The HO2 sensors are supposed to be between 200 & 800mv readings. Both Bank 1 & 2 # 1 sensors (before the CATs) are 30-50 mv while the #2 sensors (after the CATs) seem ok at around 190 &350.
The question I have is: does this mean my # 1 O2 sensors are probably bad? This isn't a tough fix and relatively cheap ($ 60 or so for the part).