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Changed distributor even boutht a new one Ebay module lasted 30 min trip and failed , pickup coil tests in spec
changed module runes again but same still
have done voltage test on earth wires ,ok even voltage drop test on earth
am looking at positive voltage test here all seams ok
have been reading that the intake air temp sender affects timing
Pontiac Fiero uses similar ecu system
http://www.fieros.de/en/articles/ignition.html

do you mean ebay module worked for 30 mins? if so, sounds like you found the problem just the ebay aftermarket module was junk. would be worh replacing it with another oem module from the wreckers.

The intake air sensor is just a trimmer and wouldn't have a dramatic effect. I think you need to look outside what you think it may be. Parts darts is expensive and these systems are really quiet simple. Getting back to the timing shift. When does it do it and how are you viewing it? Have you bypassed any of the relays?

Air temp sensor (if its the 1.8, the 1.6 doesn't have one) will really mess with spark timing. Likewise for 12p. After converting my bug to delco and not having an IAT sensor, spark timing was pretty much random no matter what was commanded.

Sounds more like the spark module to me though