I have a 91 3.1 V6 that was gifted to me for my 18th birthday. Car started perfectly fine with no issues whatsoever. The car has been sitting since 2015 and only had one issue that was visibly seen, leaky head gasket. Car has 66,657 miles and apparently leaky head gasket is really common at 60,000 miles. Car would start fine and was able to move around the house with no issues whatsoever. But when the car went for its first drive on the road it started the stutter when the throttle was pushed. So we parked it in the driveway of a potato house. After a week of fixing on the side of the road, we replaced fuel filter m, fuel pump, injectors, rotor cap and ,distributor cap. After replacing these components the car ran perfect again, but now has a very faint tick. Other than that I drove it on the road no issues, after a couple days of driving on the road at a red light it suddenly started to bounce RPM from 500 to 1500 RPMs. It would either stall out completely or go back to normal and run fine. I did replace the IAC and it seemed to have this issue happen less. I did do a test in my yard where I started the car and did not move it at all, after 10 minutes the car started to fluctuate RPMs again 500 to 1500 RPMs and then it just stalled out. I went and started it again ran good. Went and put it in storage as winter was approaching.

I'd like to get this issue fixed when summer comes around as this is embarrassing to happen at a red light or just in general. I didn't mention it in the beginning but my aunt was the one that gifted me this car and has high value to me.

Any help is much appreciated, thank you