Reader Question: Hi,
I have a 1996 Chevrolet Blazer that I am about to light a match to. I the check engine light has been coming on and off for about a year. Now the light is on solid. I have had the light checked on numerous occasions. The first time it came back to oxygen sensor bank1 sensor3.
I figured that with 160,000 miles it might not be a bad idea to replace them all. So, I did. Cleared the code, and away I drove. 2 miles down the road the light comes on again. Same code as before. I thought that maybe it could be a bad sensor from the parts store. So thankfully, my friend swapped out the defective sensor.
I drove for a week with out the light coming on and guess what? It is on again and the truck is running like garbage. Now, not only do I Do I have the oxygen sensor code, but I now have a horrible misfire at idle. And, a god awful smell coming out of the tailpipe, not to mention the lousy gas mileage.
Now I have done new spark plugs, wires, a distributor cap and rotor, and a PCV valve. I have also done an air filter and fuel filter. Hoping that that would cure the issue. After the tune up the misfire seemed to go away for a day or two, but the smell was still there. Two days after the tune up the misfire was back and the smell was horrible. So, the next thing I did was replace the converter. That made absolutely no difference at all.
Now when I start the car in the morning it starts right up, but if I have to go somewhere a couple of hours later, it cranks over for a while and then starts. It does not fire right up but if I let, it sit for eight hours or more it fires right up. Less than a year ago, I had a fuel pump replaced and I replaced the tank because of a hole in it.
Please help, I do not know what else to do.
The best advice I can give you is to go to the dealer and get a proper diagnosis. You have already spent 5 times more time and money yourself than if you just paid the $95 diagnostic fee from someone who knows what is going on.
If this is a small Blazer with the Vortex engine I would probably take a hard look at the fuel injector, commonly known as the “Spider”. These injectors are notorious for leaking fuel internally causing a lack of fuel pressure, which can cause slow starting and poor engine performance.
Lack of fuel pressure can also cause the engine to run lean, which might be setting your Oxygen sensor codes. You have to test the O2 sensor not just replace them because you get an O2 sensor code. So the sensors could be reading fine, but they are being feed improper data…..understand? The exhaust smell is probably due to the catalytic converter trying to clean up the lean exhaust the engine is producing.
A manual fuel pressure gauge hooked on to the engine is the best way to test the fuel pressure and the fuel injector. You can sometimes see and smell raw fuel from the back middle section of the engine and in some cases, the engine oil pan will be filled with raw fuel that has leaked into the oil valley. Sometimes you can pull the engine oil dipstick, it smells like raw fuel, and the oil is very thin and runny due to gasoline inside the engine oil.