2004 225X ProMax - bad coil?

[bb21xd]

We got the fuel pressure issue down to 44 psi so now we are working on the next problem. At WOT it turn 6500-6600 rpm and then slows to 5500 with the hot foot still WOT. It only does it after running 5-10 minutes and then seems to have a pretty good miss when it slows down to idle. If you let it cool off, it goes back to running smooth.

Spark tester shows no problem but we haven't tried it with the engine hot - you can't get it WARM on the garden hose. Is there anyway to test the coils other than the ohm meter page in the factory service manual?

THANKS!

[j_martin]

If you kill it when it's misbehaving hot, the different colored plug would be in the failing hole. Swap parts until you move it.

hope it helps
John

[bb21xd]

Good point. My friend at the dealership is taking out in the morning with the laptop plugged into the ECM. He is going to run it until it backs down and the turn off cylinders until he finds one that doesn't hurt the slower speed.

[bb21xd]

Dealership head mechanic ran the boat today after it got warm it had misfires on all 3 coils on left side. Starting to think ECU may be bad. I could believe it is a coil if only one cyl. was misfiring but when you lose 3 it seems to me like the ECU is bad.

Ideas?

Thanks!

[bb21xd]

UPDATE!

ECU was bad. New ECU installed, runs like a raped ape again!