98 saab 2.3- slight hesitation when accelerator pressed

saab
900

#1

idler pully seized- throwing serpentine belt. I told daughter to drive the three miles home not realizing waterpump was inoperative for those three miles. I changed the pully, changed the belt- upon starting the car was running rougher than normal. realized thermostat was in open positon and had been for months with engine running colder than normal. The car burped out 2 quarts of coolant from expansion tank after belt was thrown while driving the three miles. After changing thermostat- car runs at right temperature and we have put 400 miles on it but it has a slight hitch as accelerator is pressed, jiggle the pedal and the car proceeds to accererate normally. plugging in to hand held computer and get a reading of’ no data stream. car is running ok, gets good gas milage- 25- its an automatic. tail pipe is clear, no antifreeze in the oil, no oil in the antifreeze, nothing coming out of the tailpipe. I think it did burp out the 2 quarts when being run the three mile home but I dont think it hurt the head gasket. One mechanic said run it. I think when it burped out the antifreeze it got something wet and something is not right around the slight hesitation. have changed cap, rotor, plugs are good. can I send her back to college with this as it is… the slight hesitation was much worse and it almost seems to be coming out of it… would the computer take all this time to readjust fuel mix re the bad thermostat?? but it has a slight dead spot when initially accelerating… when I had first run it after thermostat change it was getting horrible gas milage and the dead spot would make the engine quit occiasonally but it has come up to 25- 26 mpg. which seems right for an automatic… and it runs almost ok. tailpipe doesnt have any steam or antifreeze smell- oil is ok- not polluted… but no data stream …coming from computer… what is PCM? one respondent seemed to think that was bad. thanks. Bryan


#2

Check for a vacuum leak.