I had a chronic oil leak in my 96SS (86k) that my mechanic told me was not in urgent need of addressing. Apparently replacing the seal would require removal of the transmission and other labor-intensive work. The car ran fine, but I eventually had the seal replaced (while the car still ran fine) a few weeks ago. Here is what was performed:
Initial Trip To The Mechanic
Serviced Rear Crankshaft Seal. This included removing the driveline, removing the transmission, removing the flywheel, removing the faulty seal, Inspecting the seal bore and crankshaft for wear, installing the new seal.
Drained Oil, Unbolted Engine Mounts, Raised Engine / Removed the Oil Pan & Cleaned Pan and Gasket Surface, Cleaned All Residual Oil From Engine Block, Cleaned Oil Pan Mounting Surface On Engine, Reinstalled The Oil Pan -Reinstalling the oil pickup tube as needed with new gaskets and seals, Lowered and Rebolted Engine, Oil Change.
Ever since then, the CEL has been on and there has been a misfire on #4, and there has been a strong smell of gas fumes. Compression tests are all good. It was noticed that the water pump was leaking, so a new water pump and opti was assumed to be the fix. Since then, I've spung for:
AC Delco Water Pump & Gasket
New Opti
AC Delco Wire Kit, SPLG
AC Delco Spark Plugs
Thermostat w/ Gasket
Tee Connection
AC Delco Fuel Injector Seal Kit
Fuel Injector Cleaning/Overhaul
The misfire on #4 persists. And, ever since the parts I mention directly above were replaced, the CEL flashes almost all the time. I should note that the first opti replacement didn't fix the issue so it was replaced again with yet another opti, in case the first replacement was a bad opti. These were purchased through a Chevy dealership and are OEM.
Another thing to note, and I hadn't thought to tell my mechanic this: before I took my car in for the oil leak, I would have to prime the pump in order to get the car to start smoothly. I stated above that the car ran fine, and it did. I would just need to prime the pump for one second before starting the car. I have done some reading on the forum today and it seems that a fuel pump and/or filter issue could play a part. I would expect my mechanic to have checked this possibility already, but I will ask him later today.
He advised me to drive it on the freeway a bit, in case there was carbon buildup that needed to be burned off, so last night I had it up to 4000 RPM (got the car up to around 110mph) in small spurts, and drove for about an hour straight at an average of about 70mph (maybe 2000-2500 RPM for the most part). The temp reading never rose much above the 1/4 mark the entire time, so the engine didn't seem to be very hot.
The issue still persists. My mechanic has given up and has advised me to take it to a machinist with engine expertise.
Can anyone offer any thoughts as to what might be the cause of the #4 misfire?
Initial Trip To The Mechanic
Serviced Rear Crankshaft Seal. This included removing the driveline, removing the transmission, removing the flywheel, removing the faulty seal, Inspecting the seal bore and crankshaft for wear, installing the new seal.
Drained Oil, Unbolted Engine Mounts, Raised Engine / Removed the Oil Pan & Cleaned Pan and Gasket Surface, Cleaned All Residual Oil From Engine Block, Cleaned Oil Pan Mounting Surface On Engine, Reinstalled The Oil Pan -Reinstalling the oil pickup tube as needed with new gaskets and seals, Lowered and Rebolted Engine, Oil Change.
Ever since then, the CEL has been on and there has been a misfire on #4, and there has been a strong smell of gas fumes. Compression tests are all good. It was noticed that the water pump was leaking, so a new water pump and opti was assumed to be the fix. Since then, I've spung for:
AC Delco Water Pump & Gasket
New Opti
AC Delco Wire Kit, SPLG
AC Delco Spark Plugs
Thermostat w/ Gasket
Tee Connection
AC Delco Fuel Injector Seal Kit
Fuel Injector Cleaning/Overhaul
The misfire on #4 persists. And, ever since the parts I mention directly above were replaced, the CEL flashes almost all the time. I should note that the first opti replacement didn't fix the issue so it was replaced again with yet another opti, in case the first replacement was a bad opti. These were purchased through a Chevy dealership and are OEM.
Another thing to note, and I hadn't thought to tell my mechanic this: before I took my car in for the oil leak, I would have to prime the pump in order to get the car to start smoothly. I stated above that the car ran fine, and it did. I would just need to prime the pump for one second before starting the car. I have done some reading on the forum today and it seems that a fuel pump and/or filter issue could play a part. I would expect my mechanic to have checked this possibility already, but I will ask him later today.
He advised me to drive it on the freeway a bit, in case there was carbon buildup that needed to be burned off, so last night I had it up to 4000 RPM (got the car up to around 110mph) in small spurts, and drove for about an hour straight at an average of about 70mph (maybe 2000-2500 RPM for the most part). The temp reading never rose much above the 1/4 mark the entire time, so the engine didn't seem to be very hot.
The issue still persists. My mechanic has given up and has advised me to take it to a machinist with engine expertise.
Can anyone offer any thoughts as to what might be the cause of the #4 misfire?