My '93 areostar barely keeps itself running after a cold start. It will start up, rev up, and then almost die. It will repeat this reving up and down cycle until one of the following coditions exists: the engine warms up, the air conditioner is turned on, or the transmition is shifted to something other than park or neutral. Earlier replies to a similar post on this board mentioned the idle air control valve and/or the coolant temperature sensor. I think the IAC and the Temp. sensor are OK becuase it idles fine after the conditions are met. Any ideas??

 

have your tried the tps on the ford it will start to go and cause these condition yet it will not be bad enough to throw a fault code i have come across this condition several times in the garage i work in good luck

 

Your coolant level could be too low and/or you have air in the cooling system. Either way, the loss of contact with the coolant temp. sensor causes the engine to surge until coolant hits the sensor dropping RPM back to idle. I believe one the EEC-IV system,the A/C input overrides the temp sensor which is why the engine idles correctly when the A/C is engaged.

 

If the coolant level checks out properly, then try cleaning the Mass Air Flow sensor with electrical contact cleaner. After reviewing posts from other conferences the consensus opinion seems to involve either the MAF or idle air control valve.