Intermittant no more '90 Laser

[Leadfoot_90]

'90 Laser RS runs great on 3 cylinders

I am an original owner of a 1990 Plymouth Laser RS and have been having intermittant engine trouble. I think I have short in the engine control somewhere and wonder if this sounds familair to anyone out there. Here's the whole story. (If you want to cut to the chase the last paragraph has the vitals only)

About six months ago the check engine light came on and I had a significant drop in horsepower. The engine ran a bit rough too, but It would idle and run, so I drove it the 2 minutes back home. I looked for loose wires and finding none had no clue where to look next. The next day I started it and the same low power condition was still obvious so I had it towed to a local garage. The guys at the garage bitched that they couldn't get parts for it and after a month had put in a re-built computer and some relay block (or something) and pretty much said don't bring it back here again.

It ran fine for about two months and the check engine light came on and the horsepower dropped again. But it only lasted for about a minute or so then came back to full song. Ever since then the problem was happening about once or twice a month for only a few minutes at a time. I would rev the engine to about 4K or 5K a few times and it would come back to it's normal peppy self. The tack would, when having problems, would read out steadly at about half the actual RPMs. I could hear the engine turning 4K but the tack only read 2K. This went on till Christmas day, when driving the 60 miles home from my Mother's house the problem hit and didn't let go. I could still drive 65 MPH on the highway but had next to no acceleration. Over the next few days the problem was consistant with only a few intermittant moments where it ran decently.

Enter the Mitsubishi Service Center. I limped it over to them and told them it was only running on 3 cylinders and was way down on power. A few hours later they said their were two problmes. 1) platnium plugs (I can't believe they would cause any problem but the service guy said they are in some way not happening. If anyone can confirm this or explain in any way, I'd like to hear that just for kicks. It sounds like a load of Dealer BS to me.) and more importantly 2) the valve cover gaskets had leaked oil all over the plug wires, causing the problem with the plugs getting fouled with fuel. Or maybe it was just the platnium fouling the plugs, anyway two plugs were fowled and they replaced the plugs, plug wires, and valve cover gaskets. (again this sounds like BS) The car ran great for about 10 miles and the problem came back tonight. Is this service guy gonna try and tell me it's mufler bearings next, I might buy them.

So here it is: Intermittantly (30 secs. to a minute or 2) once or twice a month for six months, low on power, barely able to do 65 MPH, Tack reading half the actual RPMs, Now not intermittant. When the problem first showed, changed for rebuilt computer (did not fix) Last week had the Mitsubishi Dealer change the fuel foweled spark plugs, the plug wires soaked with oil and leaky valve cover gaskets. This fixed the problem for about 10 miles and it's not intermittant any more. Seems to be on 3 cylinders to me.

Sound familiar to anyone? Any leads or ideas on how I might procede would be appreciated.


Original Owner of Stock '89 Plymouth Laser, and I still love it.