89,z28,5.0, auto.Just purchased and when I got he says that on the highway that it will want to die. but doesnt. Pull up to a red light and it will some times cut out or almost die. And also will start in gear. Found out the hard way. Sounds to be a sensor but not sure which it might be. Also the "shift up" light will pop up right when you take off, and theres no reason for it to come on. Any help would be appreciated thanks in advance guys.

 

Is the check engine lite lit? If it starts in gear, it is probably because the neutral safety switch is bad, or someone messed with it. Failure to idle properly may be caused by a bad IAC valve or a bad TPS, but "may" is the key word.

 

The check engine light is not on. I would think that the NSS is bad or is messed up. I will take a look at it when I get my floor jack back. Its under a car as we speak. What is a IAV valve, and also were is the TPS all located at.

 

??????

 

IAC valve is idle air control valve i believe. that and the tps i believe is on the throttle body

 

is it possible the car used to be a manual tranny? my automatic doesn't have a shift up light and that might explain the "starts in gear" part. is it possible to rewire the tranny wrong and activate the torque converter lock up with the starter lock out circuit? that could possibly explain the engine dying or idle dropping at stoplights. just thoughts....

 

my 89 rs is an auto and has the shift light.
when i manually shift it it kicks the shift up light on between 5k-6k rpms.
but mine oddly has some issues also. if i rev it and let of it bogs down just below 500 rpms an goes back up to 750. and sometimes when idling it will fluctuate from 100 to below 500 sometimes dieing. i think i know the problem as when its doing this and i wiggle the comp water sensor it dies. but that dont explain how i can still shift out of park when the key isnt in the ignition and off..maybe unrelated but yeah i have the shift up light and somehow it works with my auto trans...i think its kinda cool... i want to rewire the shift up light to a tach instead of the ecm...the ecm learns when to kick the light on by the way you drive and when you shift. or so i was told it does in manual cars as my s10 shift light comes on later when im ragging on it for more than 10 mins