So I just got my new TH400 in and finally got a chance to take it down the road to test it out. Shifts and drives fine but I noticed that I have a weird misfire. Its only evident when im trying to maintain a certain speed or RPM. If I accelerate or decel it's fine but anytime I hold the same speed for more than a second or so I get a bad misfire. There is no throttle hesitation or stumble and no backfiring.
I didn't notice it with my Quadrajet that ran pig rich. A few months ago I swapped on a Proform/Quickfuel 750DP. I got it from a buddy cheap, cleaned it up and swapped it in. Ran fine in the garage with minor mixture screw adjustments but I haven't been able to drive it until now. I played with the timing a little bit but it really didn't change anything. Primary jets are .077"s and secondaries are .084"s. Judging from my plugs it is still running pretty rich as they are still wet. Any ideas as to what is causing this miss?
I didn't notice it with my Quadrajet that ran pig rich. A few months ago I swapped on a Proform/Quickfuel 750DP. I got it from a buddy cheap, cleaned it up and swapped it in. Ran fine in the garage with minor mixture screw adjustments but I haven't been able to drive it until now. I played with the timing a little bit but it really didn't change anything. Primary jets are .077"s and secondaries are .084"s. Judging from my plugs it is still running pretty rich as they are still wet. Any ideas as to what is causing this miss?