the problem is back again....i have replaced
the lambda, the coolant sensor,the air temp sensor, spark plugs, fuel filter.
It hesitate when i floor the pedal and sometimes
it runs great!!??. It backfires when cold with
full pedal, and sometimes it dont't!!???.
It's a 2.0 16v 96'.
Backfiring is a symptom of fuel starvation or the timing being out. In this case it is probably fuel starvation (or a very weak mixture) as you say it happens when the engine is cold. The fuel mixture would normally be richer when the engine is cold, like having the choke on. Not sure if it is an engine management problem or...........have you tried cleaning the injectors ????