Dears,

Once every hour of driving, I am loosing my speedometer, the needle just goes to zero and this lasts for a couple of seconds or a couple of minutes...during that period, the car is driving erratically and sometimes the engine even stall , but not always ( Most of the time I can continue to drive and go home with the car "behaving sluggish", so there is gas and sparks...when this occurs, my odometer is freezed also...

There seems to be no error code stored in the ECM (just code 12 of course)...I just put a new ECM in, but the problem is still there (however I had the same trouble 6 years ago and my mechanic told me that at that time that a new expensive ECM was the solution, obuiously he did something else)....since the problem is intermittent and disappears, it is very hard to diagnose and no mechanic can help me (I am living in Belgium, those cars are very seldom)....

My car is a Firebird from 1990 V6 3.1 automatic and with cruise control, and ADS SuperChip....I am getting desperate to find the source of the problem....any idea to solve this ? Did somebody experience the same and found a solution ??

Many thanks for your help.

John