Hello,

Ive got an intermittent misfire that is most noticeble at low rpms. Its a constant putt, putt,putt,putt,putt,putt,puttt type of thing(when it happens)..

I replaced the whole ignition about 12 months ago(cap,rotor,wires, and hall effect)Then I put a set of platinums in 10/00. Im just wondering if the plugs have anything to do with it.

The other day my daughter had the car over here, and I found a wire loose at the dist cap. That seemed to solve it. But then about 4 days later it started the same misfire.

I havent seen the car since. she called and told me about the problem. I expect to lay hands on the car sometime today. Of course the first thing is to see if the wire possibly worked loose again. But if thats not the problem, then...

I will never buy platinums again, the Bosch platinums I had have failed more than any other plug I've had. They do just that. get a misfire at idle....and a miss throughtout the range.

I put in some old plugs and it ran fine, do you have the ones you took out?

If its not the wire , change the plug.

Hello,

Hmmmmm, "a misfire at idle, and a miss throughout the range", this sounds really familiar.

I didnt have the old plugs, but I hustled over to napa and picked up a set of super bosch. Installed them. So far everything is going ok.

She said it died once on her yesterday while it was still cold. But then ran perfect all day. I hope we nailed it, but Im going to avoid making a conclusion about this for couple more days.

Thank you for your input.

Do you have a theory as to why the platinums would malfunction the way you describe? I read the same thing elsewhere on the brickboard, but I couldnt find it again.

So what type of plugs would be good?? Say at tune-up time and 167K.

It is probably the wire again. This is the only car I owned '89 200 where the wires walk off the distributor cap. usually the one from the coil. When you get a look at the car again, you may want to bring a dab of Silicone rubber (RTV) and just a tiny blip betwwen the cap stem and the boot on the wire. it will hold BUT you can still pop the wires off when you have to.

It is probably not the plugs. Bad plugs will first misfire under high load, high rpm and heat along with your foot to the floor. Part throttle is not likely plugs. Platinum plugs only have one advantage. The platinum has excellent properties against erosion under the heat and firing in the combustion chamber. They can simply last longer if made properly. Piston engine aircraft sometimes use iridium spark plugs. You can put them right back in after engine overhaul.