My 93 Esprit, after sitting for two weeks (don't ever do that again), started breaking up at higher (over 5k) rpm at full throttle. Symptoms and stats:
1. 93.5 SE, stock except for S4s chip and no cat exhaust.
2. Car hesitates dramatically above 5 k and misses, and bogs at full throttle at 4k or so and then backfires as if a cylinder is loading up wtih fuel, not firing and then igniting on the exhaust.
3. Car runs fine up to 3/4 throttle and 5k rpm.
4. After installing new chip, I've had an intermittent warm up issue. When first started cold, car will rev to 2k for about 2 minutes, then to 3k for 30 secnds and check engine light will come on. Revs will then drop to normal idle (1k) and check engine light goes off.
5. Car ran fine with exhaust and chip for about a month.
6. Pulled one plug and it was badly corroded. Have a new set on the way. Will try those first.
If not, what's next:
b. Coil packs?
c. Ignitioin leads?