Trouble shooting
 

1990 420 SEL, Hello out there! Just replaced the cap, rotor and plugs. Now it is missing with very rough idle. Checked and wires were put back in proper place. Missing wasn't there before changing plugs etc. I was thinking...must be plug wires? Any thoughts?

Thanks

What plugs did you use? Have you read the various posts here about the several types of plugs NOT to use?

- Don't use platinum plugs
- Don't use resistor type plugs


I suspect that the nerd at AutoZone sold you some "premium platinum" plugs which run like crap in every older car I've ever tried them in.



-tp

Platinum plugs
 

yeah TP your right I used Bosh Platinum plus plugs. But I did check with Enrique over at MR MB one of the best MB mechanics around and he said he never had any problems with the 420 SEL's, which are older, and Platinum plugs, even using silicone wires... ?

Never owned that particular engine, but the consensus on this BB seems to be that running the wrong plugs can fry your ignition module.

I think the fact that it WAS running fine and now isn't is fairly conclusive.


-tp