Hey guys, I need some assistance, got an 87 IROC-Z with the TPI motor, the speedometer doesnt work at ALL until you hit 40MPH, and then its all shaky and off by about 10MPHs. Also, the runs run good until it hits operating temperature.. then it turns off. This is all word of mouth im going to test drive the car now and see whats up but if this sounds fimiliar to anyone please respond and if in fact this information is inaccurate i will repost. It IS in fact tripping a SES light im gunna go grab the code and see what it says.
Thanks guys
-Mike

Its an 87 IROC-Z 350TPI w/5speed (MAF system).

 

well the 350's never originally came with the 5speed
so either the 350 tpi was swapped in or the 5 speed
since ur having speedo troubles i'm guessing the tranny
the 5 speed tranny was equiped with a mechanical speedo up until 87
and a vss from 88 onward, i could be wrong
if u have the mechanical speedo check the cable, it might have melted from exhaust heated and the cable binds up, it may not be connected right
if u have the vss i cant help you, i have no experiance with those

 

Follow up: In case anyone else has had this problem. I set the timing, adjusted the IAC valve, and adjust the TPS. Car runs like a dream.