A few days ago I went for a drive and my 93' 80 series began to rumble whenever I would accelerate. It felt equivalent to driving on a washboard road. It was especially bad above 55 MPH. I was smelling exhaust and the idle was noticeably low and inconsistent. At this point, the car doesn't seem clear to use until I fix this problem. I checked the distributor cap for moisture and it was clean. Then I ran OBD1 codes and got 21 (O2 sensor) and 71 (EGR system). Besides this misfire problem, the car runs great and has a clean record of repairs. If anyone in the area knows a trusted shop or might be able to help me diagnose/repair the vehicle, please reach out. Thank you
93' undiagnosed misfire. Looking for help in Southern Pines/Raleigh area.
- Thread starter ElectricSheep
- Start date
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Fj80oregon
GOLD Star
I think you kinda answered your own question replace the o2 sensors. You can test them to verify before buying new ones if you dont have a FSM download one for free in the resources section and test them. Same as your egr system every part of it is testable and the FSM describes how to. A bad o2 can definitely cause your truck to run bad and so can a egr system not functioning properly.
If you have recently driven through a puddle or ran it through a car wash with under wash, you may have water in a connector for the O2 sensors. Start there.
lumbee1
Native American
Do you know where the misfire is?
Does the misfire feel the same after a cold start and after running for a while?
Have you checked your coolant and oil for mixing (chocolate milk)?
Are you loosing coolant?
IME, a failed O2 would only cause a rich condition but not necessarily running "bad" and it certainly wouldn't cause a misfire. However, coolant in the cylinder could cause the misfire and the downstream O2 not to function correctly. I'm not sure about the EGR since I deleted mine years ago.
Does the misfire feel the same after a cold start and after running for a while?
Have you checked your coolant and oil for mixing (chocolate milk)?
Are you loosing coolant?
IME, a failed O2 would only cause a rich condition but not necessarily running "bad" and it certainly wouldn't cause a misfire. However, coolant in the cylinder could cause the misfire and the downstream O2 not to function correctly. I'm not sure about the EGR since I deleted mine years ago.
