Car shaking after changing spark plugs

Add to what Shep said: Possibly destroyed a wire or several while changing plugs.

Your car will miss at idle if the spark plug gaps are too close. Also, if you put in Bosch take them out.

Don

I'll cocurr with the others...cracked insulator or damaged plug wire most likely, gap not so much so, but possible...if they were platinum plugs with the preset gap, they are rarely ever wrong...the electrode is tough as hell and doesn't bend easily..

I agree also, Bosch Plats are crap, I'd throw them away if that's what you got, get Motorcraft or Autolite for it...

I replaced my wire because I came into a new set for free, an that problem of yours I had for years went away.

Don't know what is wrong with the suckers, but if you put them in a Jeep

4.2 carb engine and in most Jeep 4.0 FI engines, they will work for a few miles, then they carbon up and the engine starts running like crap, especially at idle. Pull them out, put some real plugs in like Champion and bingo, the engine runs well again.

I have seen this well over a half dozen times in the last few years and the fix is always to toss the plugs out.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

It's called empirical data, or experience....

I'm seeing replies here similar to my experiences with Bosch plats....fouling, unstable idle, short life, etc. Same thing I've noticed in my own cars when I tried them, as well as customer's car (who insisted that I install them, against my advice, and nearly always came back within a month or two wanting them replaced for the reasons listed above...)

I got Autolite, the basic ones, less than two dollars for each.

I don't know what wrong with them but I DO know that they will cause a misfire that can be fixed by doing absolutely nothing other than putting NGK or Denso plugs in the car. I have heard many reports of this and was sceptical until experiencing it myself a few times.

Don

Why no Bosch?

How about personal experience. Customer brings vehicle in complaining about poor idle, miss under load, hard starting, poor mileage, etc..... Customer states vehicle had tune-up anywere from one week to six months ago. Tune-up looks good except Bosh plugs were used. Replace Bosh plugs with quality plugs and driveability problems are gone. I have seen this happen dozens of times. Bosh plugs are JUNK!!!!

That's exactly right! WHY they don't work I don't know.

Don

WOW,

AM i glad i read this post this morning.

I just installed Bosch platinum plugs in my 1995 Buick Century 3.1

a week ago, and it is at idle, doing a little "sputtering"..

It is drivable (other than my new problem of power steering fluid leaking on the drivers side underneath coming out pretty good...........not sure yet what it is...havent had it checked out...i mean the reservoir and pump and main hoses are on the passenger side, and now the leak drippings are coming down on the DRIVERS side...?

When i can i am going to buy some other plugs.

But i am getting about a half quart to about 10 miles of powersteering fluid right now!

I have never used the Platinums, but I have been using the usual $2 Bosch plugs for thirty years and never had a problem. They're a little more expensive than Autolite or NGK but they seem reliable.

--scott

It's the plats we're harping on...I have no issue with Bosch standard plugs.

These plugs came out of the bosch book for the applications.

I mentioned two types of fuel systems and two types of ignition systems with totally different coils.

The same complaint is posted a fair bit in the Jeep newsgroups. It is common. Those engines just don't like those plugs or Bosch has no clue in their North American books what plug a Jeep engine needs.....

Note all the others saying the same thing with other makes of engines.

Maybe Bosch has a defect they aren't aware of?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

I don't know...but the symptoms point to a very anemic, thin spark production...not the fat flamethrowers that American high energy ignition systems seem to like....after many issues with plugs in different makes and models, I now always go with what is OEM, AC/Delco in GM, Autolite or Motorcraft in Fords, Champion in Chrysler products, Denso or NGK in Jap makes, Bosch in the Europeans that call for them...saves a lotta hassle..

Some plugs are a proven winner for any app, i.e. I've put NGK's and Denso's in just about anything at one point or another, with no ill results....

Check the order of the wires off the distributor to the plugs. Then, as most have said, if firing order okay, you likely looking at a bad wire, bad connect at either the dist. or the plug.