90 LeSabre No Injector Signal to Cyl #1

[HannabilRox]

I have the 3800 engine with 70,000 miles on it, and it has done this since I bought the car last July. It intermittently runs on 5 cylinders. It runs like that in idle, so I was able to troubleshoot with the car in drive and the emergency brake on. I removed each injector wire one by one until I found the cylinder that made no difference in RPM when removing a wire, which lo-and-behold, was cylinder #1. I connected a NOID to the injector wire and found that when I first start the car, I get the electronic signal to the injector for a few seconds, then it goes out. It will mysteriously come back on then off again randomly. I traced the injector wiring back to the firewall and did not see any problems with it. Any suggestions as to what will cause the #1 cylinder injector wire not to get a signal randomly? Oh, I checked the engine codes and it comes up with a 12 (no detected problems).

[danthemanluvatan]

Rap test the ecm with car running and noid light installed and see if the gives you power to the injector. If so ecm may have crack in circuit board.

[HannabilRox]

Had a spare ECM and hooked that up...problem solved! Bad ECM. Thanks for the help! Car runs like a champ now!