[idmetro]

I've got an 86 Sprint and the check engine light is set to come at 30,000 mile intervals (30,60,90K etc...) regardless of whether anything is wrong or not. There is a slide switch just to the right of the fuse block that you simply move from one side to the other and it turns the light off until the next 30K miles have passed (I assume yours will be the same). Our cars are OBDI so they use the check engine light to flash trouble codes. Reset your ECU (by sliding the switch) then watch for the light, if it shows up again then you can read the codes and see what it's telling you (to read the codes you turn the key to on but don't start the engine and count the number of times the check engine light flashes). Also I don't think there is any connector for a scanner.
With your V8 background your squirrels will likely feel like they are holding back even when running in top form. I should mention that mine feels like it pulls strongly up through about 1/2 to 2/3 throttle and then noticably slows, it's done this since day 1. Do be sure to run some fuel drier/cleaner through the system after it having sat for so long. I've had good luck with HEET and Seafoam.
Also clean out your EGR valve and the passages in the intake manifold they get clogged and dramatically affect the performance of the the squirrels.