I've got a strange misfire that I can not figure out, and I thought it would see if anyone has some ideas.
It is a 98 Mini with the MPI fuel injection.
The car has dead miss on cylinders 3 & 4.
Here is what I know:
I first replaced the plugs and wires because they were blasted out anyhow
Then I checked to verify that I had spark - I do on all 4
Then I checked my fuel injectors for power and ground - Noid light flashes the same for both injectors. So, I then switched the injectors to see if the misfire would follow, and it doesn't.
After that I did a compression and leakdown test, both passed perfectly.
So still baffled, I then removed the coolant temperature sensor and tested it - passes fine. Check IAT sensor - passes test. Checked TPS sensor - passes test.
What I found out then is that cylinders 3 & 4 are being heavily washed out with fuel. Both pistons are very much cleaner than 1 & 2, and when I unplug cylinder 3&4 injector the idle smooths out instantly, just for a few seconds until all the fuel is burnt up and then it resumes its misfire.
Any thoughts would be greatly appreciated. Thanks!