I have a friend with a 1993 Mitsubishi Diamante ES. I did new plugs and wires (two wires contacts were not in properly and corroded, and one of the plugs actually broke when I took it out...ish...) and started it up and discovered another problem.

Occasionally, while it was idling, it would suddenly cut out and sort of stall, but recover in a second. When it cuts out, there is a click from over near the glove box area, which I'm assuming is the computer doing something. While it's half stalled, for that one second or so, the check engine light is on, and it goes back off when the engine recovers.

I know this car has had a little issue with the check engine light. Once in a while (not often), when starting the car up, the check engine light would come on....but in those cases, the engine did not seem to have any adverse running conditions. Turning the car off and starting it again would seem to remove the light.

After sitting a minute, the cut-out problem seemed to go away, though I did not want to continue running the engine with it doing that, so I did not keep it going for more than a couple minutes (the temp gauge was just starting to rise). I also have not driven it anywhere since.

I'm more of a Caddy person when it comes to knowing the car well, so this thing is a little foreign to me, and I do not know how to read the codes on it. If someone could assist me in what might be causing this, I'd be grateful.

Update: For diagnostic's sake, I drove it down the road a bit. It did happen a couple times while driving as well. It manifested as an rpm drop (I'd say 200-300 rpm), and one of the times I felt it jolt while doing so. The jolt seemed less when I was cruising back (sort of down hill continuously) with the O/D off.

OK, I've been able to duplicate the problem enough now to know it's the A/C compressor that's clicking...and I guess sort of catching and putting more strain on the engine than it's supposed to....so if that means the compressor's shot...or going...or it's just low on refrigerant?