92 SC started running rough and losing power when it hit about 45mph, The engine quickly deteriorated to where it ran rough all the time and would barely idle, sometimes dies at idle. CK engine light stays on.
We got codes and it said coil #3 failure. We replaced the coil pack with no improvement, so we went forward with replacing all the plugs and wires, too. Still no joy. Checked codes again, the previous one cleared , but it said MAF , so we replaced the mass air flow sensor and the mass air pressure module. Still no joy. Checked codes again and the previous ones cleared, but it gave codes for one O2 sensors and coil #3 again so we replaced the O2 sensor. Still no joy; but the coil code cleared and It then gave code for other O2 sensor, so we replaced it,too. Still no joy. Checked codes again and it still says one o2 sensor is bad and that it now can't get sufficient rpm change for tests.
I feel like we are just chasing codes around. We have checked vacuum lines and wiggled connectors over and over again looking for a problem, but just can't seem to track it down. However, it is interesting to note that as soon as I hit the "test" button on the code reader, the engine levels out nice and smooth. When it finishes testing, it goes back to running lousy.
Every now and then on the road, it will suddenly start running right for just a minute or two then go right back to limp mode.
Has anyone here solved a similar problem? Help!
We got codes and it said coil #3 failure. We replaced the coil pack with no improvement, so we went forward with replacing all the plugs and wires, too. Still no joy. Checked codes again, the previous one cleared , but it said MAF , so we replaced the mass air flow sensor and the mass air pressure module. Still no joy. Checked codes again and the previous ones cleared, but it gave codes for one O2 sensors and coil #3 again so we replaced the O2 sensor. Still no joy; but the coil code cleared and It then gave code for other O2 sensor, so we replaced it,too. Still no joy. Checked codes again and it still says one o2 sensor is bad and that it now can't get sufficient rpm change for tests.
I feel like we are just chasing codes around. We have checked vacuum lines and wiggled connectors over and over again looking for a problem, but just can't seem to track it down. However, it is interesting to note that as soon as I hit the "test" button on the code reader, the engine levels out nice and smooth. When it finishes testing, it goes back to running lousy.
Every now and then on the road, it will suddenly start running right for just a minute or two then go right back to limp mode.
Has anyone here solved a similar problem? Help!