Hi,
1993 Chevy S10 Blazer 4.3L Vortec 4x4 auto, @191K mileage.
It has been running extremely rich and throttle even in neutral sounds sluggish like it is clogged and having trouble clearing out. If I mash the gas, it accelerates rough, but then clears up and runs smooth. Slowing down and the throttle response repeats itself almost like it is drowning itself. If I drive it up the road, it is very sluggish and feels as it is being held back until the speed increases and the throttle smooths out again. This happens continuously. Blue smoke out tailpipe and choking fumes and eye burning too. Black spots from rich exhaust also on grass.
My scanner Actron code reader said code for HO2 sensor rich. I replaced with a new HO2 sensor, started it and it ran no different. I reread any codes and this time I got the opposite saying HO2 sensor lean. It feels like it get's good pressure out the tailpipe so i don't think it is cat converter related. I dropped the oil and it overflowed out of my container there was so much gas in the oil. Not good for the engine. It's been a week or two of running it very sparingly and the oil looks overfilled again.
I've changed parts over the past few years like fuel pressure regulator, MAP sensor, EGR sensor, plugs, wires, cap n rotor, fuel filter a few years ago. I'm going to redo the fuel filter because it's good maintenance and I can rule that out. About 2 years ago I did have to open the intake plenum because a plug/hose came off one of the injectors and it was leaking in. I plan to open it again and recheck everything. Can anyone share any ideas or similar occurrences they've had with these older S10 Blazers?
Thank you.