[STPilots5150]

I know the MSD80 ecus are known to fail and misfire on a full bank. Has anyone heard of a MSD81 ecu having the same failure? I have MSD81 and have a full bank 1 misfire and have replaced the primary o2 on that bank, all 6 injectors, all 6 coils, all 6 plugs, cleaned both vanos solenoids and checked compression. I still have the misfire on cyl 1-3. If you fire it up, it idles fine with no misfires. If you go to drive and give it any load, it will misfire and shut down cylinders until next startup. The fuel pressure increases with throttle angle, and the misfires are consistently only on cylinders 1-3 which is why I believe it is not fuel related. Any input will be greatly appreciated. Thank you

[catcher22]

Never heard of an 81 having issues, however the symptoms sure do sound similar.....

[MysticRob]

A recurring theme I've read here is if the usual suspects don't resolve the issue then it could be a partially blocked and/or plugged catalytic converter coming off that one bank. In other words, it may not be anything upstream, but downstream of the cylinders causing the engine to not properly evacuate all gases after the combustion process.

[STPilots5150]

Yep that's what it ended up being. Sorry I didn't close the thread