89 Chevy Sprint takes about 5 minutes to warm up to be able to drive away or it stalls when I give it gas. The engine will rev up for 3-4 seconds then drop down and almost stall and then rev again during the warmup phase. It will hesitate once warm but it will run although not great. I have found that if I remove the vacuum hose for the map sensor cars starts right away and I can drive away with no hesitation at all but it does rev a little higher then normal
Cars & Trucks - Chevrolet - Sprint
Answers & Comments
Plug the vacuum line you unplugged and the idle should come back. Change your air filter and the map sensor. check for correct coolant level and replace the coolant temp. sensor. This sensor affects cold starting and idle through the ECU (open loop mode, rich fuel mapping and 1200 rpm idle) It should go to closed loop mode in the ECU once engine warm up is achieved ( lean fuel mapping and normal 900 rpm idle). Do not unplug anything else till you perform an OBDII scan of the stored fault history