quote Originally posted by gtxbullet: no change with wd40. have codes 15 - coolant temp 24 - speed sensor 33 - map sensor (only happens when it stalls) 42 - ignition

Have you go through the diagnostic troubleshooting flow charts in the service manual for each individual code?

quote Originally posted by gtxbullet: the issue has to be in the wires.

Assume nothing. Verify everything.

Follow the diagnostic flow charts...

Did you ever figure anything else out? I'm currently sitting in an 88 2.5 with similar issues.

Yeah Im curious. My 88 duke is acting similar but my computer is feeding me no codes. No flashing when I cross the terminals. I have another 88 duke and it threw me codes with is good the standard 3 blinks to make sure everything is in order. I moved the ECM and same deal, no codes.

Same same, I have 2 cars doing this same thing. One was fine before but I swapped some parting including the ICM and coils off my good running car along with my ECM, MAT and entire throtile body. The car with the issue still had the problem so i moved it all back and the good running car developed the same symptoms. I think its an issue with the ICM. It got fried or soemthing. is there a way to test an ICM for issues? Car still runs but pops/missed and wont hold an idle, also hard to start.

The issues I was having went away.
My guess was a ground issue.

Considering I've had every part off the frame/car at least once, including an A/C all powered option interior harness and engine harness.

quote Originally posted by gtxbullet: long story short I put my 2.5L back in my 88 and sold my 3.4L swap to buy a fastback daily driver. ================================== here's the details: Starts fine, idles good for a couple minutes after a couple minutes the idle rpm's sort of wander very oddly. not reving up and down, but gradual when driving it sometimes wants to stall (and does) while shifting into another gear (manual) or when coming to a stop. when I'm stopped in traffic the rps kick down then up A LOT, to the point I need to keep my foot on the gas so kids don't think I want to race them...lol when the engine is running it sounds like it's very slightly putt putting. ========== ========== here are the things that are new or have be tested and have ZERO ISSUES: brake booster (and all connections between the booster and the engine) fuel pump - new Pump Strainer - new fuel filter - new fuel pressure regulator - new Every engine seal and gasket was replace (full deconstruction and rebuid - this problem was happening before I did this) MSD Coil Packs ignition module - new Crank Sensor - new Spark Plugs - new Spark Plug Wires - new Power and Ground cables - new PCV - new EVAP System has been checked and bypassed - issue doesn't go away EGR - new Computer (PCM) has been swapped (1988 5-speed and 1987 5 speed, no change) no catalytic convertor (though I'm going to be putting a high flow unit on to quiet it down again