[auIILTD]

Originally Posted by rayhines

I got a AU I 1999 Forte Wagon, converted to gas.
It was running rough and missing, so my gas guy diagnosed new plugs and leads and tweaked the computer settings. Seemed ok but on way home it backfired once. Then for next few weeks it would backfire at least once a day. Eventually it got a bit worse, missing, even on the highway, and to the point it almost stalled. I switched to running on petrol only, which was better, no backfire but after a while it also missed and ran rough occaisionally. I was thinking it may be electrical - like the coil pack arcing?

Went on holiday for a month and came back - the battery was flat. I charged it and started it on gas - it drove like a dream, no backfire or missing, smooth idle even with AC on. Conclusion - resetting the computer due a flat battery fixed all the problems! My mechanic had no idea about this, wish someone had suggested it months earlier, saved me running on petrol for a few months at more cost!

You will probably find that your car will tend to go back to it's old habbits. Resetting the ECU does nothing more than erase the learnt long term fuel trims. These trims are designed to pull or add fuel to compensate for engine wear, changes in air flow - both intake and exhaust. Ideally, your trims should only be erased when you have made a change that will impact on the air / fuel flow through the engine - such as exhaust / CAI etc.

There may be other 'items' erased with a reset too, but I certainly are not aware of them, and I have not read of any in my tuning research.

Hope that clarifies a bit.

Cheers
Stu