They say no good deed goes unpunished: I recently changed spark plugs in my '92 500E and on cranking it up, there was a definite but intermittent ignition miss at idle. It didn't run up bad, but it did sound different during acceleration. I got someone to put it on an ignition analyzer yesterday and it showed the number 7 cylinder firing odd. He pulled the plug and found the gap way too tight. Yes, I was VERY careful about gapping each plug and torquing them in properly. The only thing I can figure is when I inserted it in the hole I bumped the electrode enough to bend the electrode in.

It's amazing the force it takes to bend that electrode when you're gapping the plugs, but bump it just right and it'll move a mile!

Good thing is, it's back to idling glass smooth and running like a scalded 500E dog!

I'm glad you found it Tim. I have seen techs do this as well. I use a special long spark plug socket when I work on the 119. It holds the plug very tightly. I start by hand, then tighten with a ratchet.

------------------
Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

Glad it wasn't a wire! Your advice on this is appreciated...

Keep the hammer down, amigo; carbon's the enemy

PS If you're getting better than 15 MPG, you're not driving hard enough!

------------------
All the best, Michael
500E
300TE

Indeed, I just dumped a bottle of Red Line Fuel System Cleaner in (couldn't find B&G 44K), prior to my oil change this weekend, hoping to get rid of a bit of that carbon.

You mention MPG. Since I don't have a G-Tech (hint, hint), gas mileage is my easiest gauge of tune. Filling a 24 gallon tank once a week allows for some regular monitoring. I can go a week babying the car and get 20 mpg, I can go a week routinely passing folks and if there's room and little traffic staying on it to 110-115 and STILL get 20 mpg.

I'm interested to see if it picks up even a little with new filters and plugs in it. If not, it's still a hoot-and-a-half!