8v 2.0 Dohc '92 Sierra Engine problem!
 

I have a 8v 2.0 dohc '92 Sierra engine with a downdraft webber carb, it runs on 4 cylinders until you hard accelerate, then goes onto 3 cylinders and backfires. When you slowly ease off, you can override the problem so why is it doing this? Is it the ht side of it or is it carby side of it?
Would appreciate any feedback.

Cheers

Is the carb set up right.

Change the plugs, leads, rotor arm and cap, then see where you're at

How can I tell if its ht or carb side of it?

The carb feeds all four cylinders so a single cylinder misfire can't be caused by the carb.

Exactly this