I went to start the car yesterday morning. Cranks over great but no start. Fuel pump is priming. Checked for codes and I get 21, 22, 33, 34, 42. The codes don't make sense to me. I don't get how the TPS volts can be high and low at the same time or how the MAF can have high and low signal at the same time. Last night when I got home the car started just fine. I checked the connectors for the TPS, MAF, and the relays. I looked at the connectors on the ECM. I tapped on all of them with it running and there was no change at all. I started it a few times. Came back an hour later and it still started fine. Worked on the wife's car for a while. Came back and still started fine. No codes at all. Go out this morning and no start again. Same fives codes. Strong fast crank. Only chugs like an attempted to fire once in a blue moon. Just trying to find a good place to start checking things. I replaced the TPS last week along with the connector. Set to 0.57 volts. The only thing that changes from morning to evening is temp. Just looking for a place to start troubleshooting. Thanks in advance.

 

Sounds like a bad ecm. What are you missing when it doesn’t start. Fuel pressure ok. Spark and injector pulse ?

 

This afternoon it is also not starting. Only have code 21 and 42 now. Double checked that TPS is set good. I am missing spark now that have time to work it and it is messing up. Now to go from here.

 

So I found that the connector for the pickup coil was a bit rusty. Cleaned that up but still no spark. I them found the coil to cap wire had burned through at the cap side. It was crispy all through the boot. Swapped in a spare I had and she fired up. Idled just fine. Started it a few times. No codes now. Hopefully good in the morning. If not back at it again tomorrow.