RealLow4.2

so ive been looking for the problem for some time now... my cars a 90gt supercharged 80mm mass air, 70mm throttle body, 42# injectors, cobra upper and lower, gt40 heads, b303 cam, 255 fuel pump, msd 6al box, motorcraft dizzy and wires, new plugs. Ive had a stumble for about 2 months now to the point i couldnt even drive it... its cleared up since i cleaned my mass air and filteranddid IAC, TPS, EGR, and fuel filter however its STILL hesitation/missing/stumbling at like 1700-1800 rpm... What could be causing this now? My car currently is overheating so i did a new radiatior but i believe the thermostat is sticking... i dont think that wouldcause it to be missing but i dont know... im still a kid and this is my 1st mustang. But ineed this problem fixed so i can atleast enjoy my car... Does anybody know what i should do?


p.s.- should i geta 180* thermostat or stay with the stock one?

chazmcgee

what do your plugs look like when you pull them out?

RealLow4.2

the plugs were a little blackened with i assume carbon from running rich before i replaced stuff, but i cleaned them up to brand new looking...

aabensonae

How much timing are you running? But then again I am having a similar problem and it sounds like the water pump in mine is going out.

RealLow4.2

i never even thought of the water pump... my car has been overheating so i replaced the whole radiator becuase there was a pinhole leak on the passenger side... drove my car for 2 minutes down the road it the temp gauge was heading to the red still... Do you think maybe my water pump is gone and thats causing my cooling problems as well as my hesitation/ drivability problems?

as far as my timing, i believe its 14* but im not sure... my mechanic timed it for me

RealLow4.2

my check engine light has come on about 5 times randomly but goes off after about 10 seconds...... ????

aabensonae

I know that water pumps if they get clogged they can start to vibrate because the water flow is uneven and that effects how the fan spins. If you have your car idling listen to the water pump area and see if you hear anyalmost like growling or in some cases a lite grinding it is most likely the water pump on its last leg. It may whistle when you rev it if the bearing are going out. If the bearings are out you should be able to grab the pulley and wiggle it. You may have to take tension off the belt to check the wiggle. Hope some of this helps.

94StinkinLincoln

14 degrees of timing and a s/c...this wont wind up good at all. thats asking for a detonation.
get a tune!

badtzmaru

^^^^^^^ same answer.....

RealLow4.2

that 14* was a complete guess... i have no idea... but my car was tuned my performance dyno......