Made some diagnostic progress on the 385 Mini-ram

[Plantfoam]

My car has been acting up for quite some time, and I have thrown a few parts at it (primarily ignition-related) without much of a change in results. The engine had been running great on a cold start, just like when we first completed the swap. When the engine gets hot it stumbles while in gear and under low to moderate acceleration. Recently, that stumble became a dead miss, and I started getting a lot of exhaust backfire while decelerating under load.

I swapped in new plugs last weekend (should have done this sooner) and all seemed normal except for #2, which was black. We drove it to The Bricks and back, and the new #2 plug was already black from 50 miles of freeway driving.

So, at least now I know what cylinder is causing me trouble. I did a compression test on 1 and 2 today.
#1: 160, 160, 165
#2: 180, 185, 180

Could it be higher from carbon buildup? I guess it could be acceptable as well, as it is within 10% if you go with the 165/180 results. I'm thinking this at least eliminates valves as a problem...We also put a test light on the injector harness and it seems to be pulsing correctly.

What do you guys think? A bad injector?

[Plantfoam]

I went ahead and ordered a replacement injector...Go figure that the cheapest place that had it in stock was Amazon After some discussion, we decided that this pretty much has to be it...Accel kinda has a bad rep for DOA injectors, but I guess it can happen with other brands as well. Will let you guys know how it turns out....I've wasted most of this summer driving on 7 cylinders, so hopefully I can salvage something out of this.

[jakes_GSXR]

Good luck and I hope you've figured this one out.

[Plantfoam]

I hope so too...It's just one of those things where you go over all of the obvious things, and it ends up being a bad part that you trusted all along. I'm just happy that the compression test turned out ok...my main worry was that I had a bad valve or something.