my 92 z28 5.7 will start up and run perfect. but when im driving and let of the gas the rpms begin to drop slowly into a stall. unless i 2 foot the pedals(just keeping the rpms up a little as i slow down). now i just installed a level 2 700r4 in the car a couple weeks ago. and during the install we cracked the speedometer drive gear very slighty trying to fit it onto the trans output shaft. it worked fine until the other day. the gear must have completely broke off because my speedometer is dead . and this is the same time the stalling began. but i was told that the speedometer gear breaking should have nothing to do with the stalling. so here i am looking for help.

 

Yeah, I wouldn't think that would have anything to do with the stalling. The stalling is most likely caused by a poor air/fuel ratio which usually is the result of bad sensor/s, vacuum leaks, or timing. Is it throwing any codes?

 

its not throwing any codes. and if i stayed in first gear and just putted around a parking lot or something there is no stalling. only if i run through the gears and get off the gas. mind boggling

 

is it possible for the prob to be the trans itself? it only has a couple hundred miles on it

 

Im not that knowledgeable when it comes to engines but maybe it could be the IAC, I had similar problems and it turns out my IAC was broken in half.

 

i guess i can give that a try. i went out yesterday in the Z for a bit and it seemed to do it less often but the rpms still died down awkwardly from time to time. my voltage is very steady tho