Dears,

here I am again with my troubles....I changed my ECM AND the vehicle speed sensor located in the tranny...and still after 25-40 minutes of highway driving without any problem, troubles appear...

history recap :

1) a couple of months ago I was loosing my speedometer after 25-40 minutes of drive...when I say loosing I mean the needle wildly jumping to zero for a couple of seconds/minutes....during that period the car is still driving, but I have no gas response anymore for a couple of seconds (I floor the pedal and nothing) ( when I slow down the engine stalls...I restart the engine and no more problem till the next drive...no Engine Service Soon light was coming at that moment...it happened a couple of times and then I decided to look for a ECM replacement
2) after 2 months I found a ECM module and swapped it...the PROM was not working so I kept mine....unfortunately same behavior, except that now the ESS light comes on...but no error code has been stored, damned !
3) I finally succeeded to get another speed sensor (not so easy in Belgium if you don't want to pay a very high price, got lucky found one in a junkyard)....still the same problem except that today, instead of having the speedo needle going to zero mph, it stayed blocked at the same speed for a couple of seconds, same for the tachometer, but no gas response and engine stalling just after...

I removed today my ADS Superchip, reset everything and will try another trip at the end of the week..I cannot afford to come late to work for a couple of days...

Any help will be much more than appreciated....I am getting lost here with the risk of having to get rid of my firebird if I cannot solve the problem soon...

Many thanks

John
3.1 V6 Firebird 1990