daughters-car
10+ Year Contributor
- 52
- 20
- May 18, 2012
-
Celestine,
Indiana
This new car is killing me! Just fixed a whole list of issues, the last of which was getting the cruise control working and thought it was finally good to go. Then last night while teaching my daughter how to drive a stick shift, it started running terrible. We are working on a 97 Spyder GST with a manual transmission and awd swap.
We drove to town with the car running fine, stopped for food and when we started the car after it was running horrible with the check engine light on. I checked for obvious issues like loose hoses, connectors, plug wires, but didn't see anything obvious. The car was barely drive-able, definitely down 1 or 2 cylinders. I took over driving duty to limp us home. I noticed the tach and speedometer were both reading incorrectly (low), the wideband was pegged lean, and the car would spit black smoke, flames and sparks if you got into the throttle too much! We made it home and I broke out the ODB scan tool and got only one code - P0300 random misfire. Well duh! I could tell that. It was like zero degrees out, so I cleared the code and went in the house to put on some warmer clothes so I could try to diagnose without freezing to death.
After changing clothes and going back to the garage, the car started up and ran perfect! I tried wiggling connections at the CAS, TPS, ignition coils, PTU, injectors, and temperature sensor with no effect. Took the car for multiple test drives and could not duplicate the issue again. Then while letting it sit and idle, the check engine light came back on, but the car was still running fine. This time it had multiple codes, P0300, P04?? (something to do with evap), P0505, and P1105. I decided to give up for the night at that point.
The bad tach signal was leading me toward the PTU, but this car already has a new PTU, coils, plug wires, and spark plugs. I have found many wiring issues in this car while fixing other issues, so another wiring problem wouldn't surprise me either. I did some searching and see several instances where a PTU was only intermittently bad and did cause multiple codes similar to those I am now getting. Would a bad PTU also cause the speedometer to read wrong?
I have a spare PTU that I can swap, but I don't want to try that until the car acts up again. That way if it fixes the issue, I'll know that was the problem. I think I'll carry the spare PTU and tools to change it with me for a while.
Any other suggestions to diagnose this problem that magically fixed itself? My daughter wants to take this car back to college (4 hours away) with her this coming weekend and I don't trust it right now.
We drove to town with the car running fine, stopped for food and when we started the car after it was running horrible with the check engine light on. I checked for obvious issues like loose hoses, connectors, plug wires, but didn't see anything obvious. The car was barely drive-able, definitely down 1 or 2 cylinders. I took over driving duty to limp us home. I noticed the tach and speedometer were both reading incorrectly (low), the wideband was pegged lean, and the car would spit black smoke, flames and sparks if you got into the throttle too much! We made it home and I broke out the ODB scan tool and got only one code - P0300 random misfire. Well duh! I could tell that. It was like zero degrees out, so I cleared the code and went in the house to put on some warmer clothes so I could try to diagnose without freezing to death.
After changing clothes and going back to the garage, the car started up and ran perfect! I tried wiggling connections at the CAS, TPS, ignition coils, PTU, injectors, and temperature sensor with no effect. Took the car for multiple test drives and could not duplicate the issue again. Then while letting it sit and idle, the check engine light came back on, but the car was still running fine. This time it had multiple codes, P0300, P04?? (something to do with evap), P0505, and P1105. I decided to give up for the night at that point.
The bad tach signal was leading me toward the PTU, but this car already has a new PTU, coils, plug wires, and spark plugs. I have found many wiring issues in this car while fixing other issues, so another wiring problem wouldn't surprise me either. I did some searching and see several instances where a PTU was only intermittently bad and did cause multiple codes similar to those I am now getting. Would a bad PTU also cause the speedometer to read wrong?
I have a spare PTU that I can swap, but I don't want to try that until the car acts up again. That way if it fixes the issue, I'll know that was the problem. I think I'll carry the spare PTU and tools to change it with me for a while.
Any other suggestions to diagnose this problem that magically fixed itself? My daughter wants to take this car back to college (4 hours away) with her this coming weekend and I don't trust it right now.