I have a 1994 Saturn SL2 with 155.000 miles and an automatic transmission that recently started missing intermittently. It's been getting worse. To me, the symptoms are a bit unique. Basically, the car misses under load, accelerating or going up hills. (Which is, of course, when it's most annoying.) Anyway, it also misses idling in Drive at stop lights, but it doesn't miss if I put it in neutral. (Ie, the engine runs smooth in neutral.)
If the car was carburetored I will think this was a vacuum leak, but I'm not sure with a fuel injection car, I'm new to them.
I also recently changed the spark plugs, so I don't think it's them. (The miss started well after I changed them though, so I don't think I screwed putting them in up either.) The spark wires also look good, but I haven't tested them. Does anyone know what my problem could be?
You can still have vacuum leaks with fuel injection.
A miss that is predominant under load is usualy plugs, wires, or corrosion. Double check the pliugs and wires. Also remove the wires from the coils and clean the coil terminals. The coils and module also reguire a good ground. The mounting bolts and plate should also be corrosion free.