This is not for a tib first of all, but I saw this and the other cars section fit both, so I'll try here for my assumptions...

My girlfriend drives a 1998 Mercedes SLK230 Kompressor. For those of you not familiar, it is a supercharged four cylinder. Anyways... I got to drive it for the first time tonight! Pretty quick and all. Tonight was a rather cool night, mid 50's or so... I get on Lagrange Road (faster paced highway) to go out to dinner. I give the gas a little love tap and get up to 75 prettttty quick. Alyssa puts the seat heaters on, the top is down so it was chilly. All of the sudden, what I THINK was the coolant light came on, accompanied by my good friend Check Engine. The car is now running like garbage. You romp the gas only to feel a 'Pluh' sensation. So I take it easy til we get to dinner.

After dinner, I get in the car, start 'er up, and it now feels and runs fine.... So I take it to my house taking it easy, but giving a couple stabs at the go button to make sure it picks up and goes still. Every works just as those Germans intended it to. Solid, fast, streamline, perfect. I pull into my driveway, toss the scanner on it...

-p0301 Cylinder 1 Misfire
-p0300 Multiple/Random Cylinder Misfire
-p0304 Clyinder 4 Misfire

So I cleared it out and it's running fine again.

My real question is this. Do you guys think that maybe because of the supercharger on this car, it would need a step colder plugs on it, or just new ones in general? I mean, it may have been coincidence, but when the car cooled for an hour and a half, it ran perfect... The SLK has about 80,000 miles on it, no clue if the plugs/coils/injectors have ever been serviced.

Any input?

 

the Chinese restaurant owner across the street from out shop has one too... i would change the plugs and see if the coils need to be replaced. check the coil jacks for signs of dirt or corrosion. also run good gas in it for awhile.. not cheap shit.. and put some Marvel mystery oil in with the gas..

 

Only runs BP Ultimate and Shell V-Power. Best premium. I think we are going to change the plugs... I don't even know what to put in it. Probably some bosch iridium fusions...

 

If its a distributor engine (not sure) then you need to change the distributor and cap.

Had a similar problem happen on a blazer i was working on, when cold it would drive fine, when it got warm it would misfire.

Got to the point where it would only run when it was cold.

Whats happening is the spark is jumping around in the distrubutor when the car is hot.

If its not a distributor engine then plugs/wires are to blame, a friend had a distributorless explorer, misfired like crazy, plugs and wires took care of it.

Either way im sure plugs & wires wouldnt hurt.

 

Bosch platinum plugs were installed at 50k miles, and are guaranteed for 80k miles, so at 130 they need to be changed. The "Wires" on the car are coil on plugs. There is 2 coils, and a wire comes off each coil to the second and fourth plug. So, there is two coils, each coil has a boot that goes to a plug. The other two plugs are powered by a wire from the coil. The car is distributorless. I think we are going to change the coils and boots. I can get them for about 200$ from my work.

 

Damn, didnt know it was COP, plugs are looking to be the problem

I wouldnt trust plugs for 30k on a high performance car, let alone 80k

 

Exactly what I was thinking... I change my plugs almost as much as my oil... Better safe than sorry you know? Problem being... Coils, basically our wires in this scenario is the issue. Plugs are no big deal to change. But if the boots are original, we are talking about dry rotted boots, ripping cracking bending metal so it arcs, tons of issues... So a 20$ fix just turned into a 230$ fix...