i have a 1991 z28 305 tpi converted to a 5 speed that does not want to idle sometimes. the problem is hit or miss and im out of ideas. sometimes the car starts normally and runs fine, but sometimes it will only start if i feather the gas and will only idle if i give it a little gas. if i take my foot off the gas the idle will drop way down, bounce up a few times and then die out. it starts right up but does the exact same thing. after driving for a little the car warms up and the idle gets better but still is not normal. it idles rough and sometimes still stalls. i first thought that it was a vaccume leak but i cant find one, and now im starting to lean towards bad injectors, i have no idea how old they are. the car has new plugs, wires, cap, and rotor, i need a new thermostat as mine is stuck open but the idle problem started a week (at least) after the thermostat failed. any ideas would be greatly appreciated, thanks

 

sounds like a vss issue or possible iac

 

im sorry but what does iac and vss stand for?

 

idle air control (iac) vehicle speed sensor (vss)

 

where are those located on the car? i have unplugged various sensors while the car is idleing with no change

 

vss on trans tail housing the iac is on the right side of the throttlebody under the tps.