I forgot to mention that the check engine light is on while it idles rough and goes out simultaneously when it smooths out.
I fixed the fuel line but that didn't fix the rough idle. I replaced the ecu and that fixed it.Hey apex2624. Did fixing the line solve the problem? I have a 89 GT that does the same thing. When you crank it, it idles like it has a full race cam, then after about 2 minutes its like someone threw a switch and it idles great and runs fine. I have check codes, swapped out the ECM with a known good one. But have not solved the problem. Was interested if you fixed yours.