[Lous6t4gto]

fresh 1998 3800SC/4t65e-HD in 1987 Fiero. initially ( about 30 miles) it performed Great. Then sat for about 6 months, now, it will start and Idle perfect, but at full throttle, it misses, backfires (coughs through intake) and has almost no power. let off and it runs fine. New TPS, plugs gapped at .045,new Fuel, has 47 PSI fuel pressure, no plugged air filter. when trying to use a u380 reader, all it says after going through it's thing is "Linking Error". any ideas ? right now waiting for 3 new Ign Coils just to try. Thanks for your help

 

[Jay-ID]

I'm no expert but a couple thoughts:
- Are you sure the PCM isn't stuck in Park?
- Are you maintaining enough voltage? In my swap, the alternator was bad and the engine would only run well for the first ~10 minutes after being on a charger.