First off, what a great forum! You guys are awesome.

I purchased a 1995 E320 W124 M104 last week up near Chicago. It has 95k on it and is in spectacular condition. After driving my dad's 99 E430 and my mom's 98 CLK320, I fell in love with Mercedes, and I knew this would be a great car.

Anyway, I started to notice a rough idle a few days later, and then the check engine light came on. I got a code #7 from the diagnostic box, and after reading here about that problem, I figured I should change the spark plugs and the connectors on 2,4 & 6. I purchased the correct Bosch F8DC4 plugs and connectors, and was ready to put them in. I pulled out the old plugs, and they were AC Delco brand, and the gaps were in the .43-.46 range! I set my gaps for the new plugs at .31, installed the connectors and was ready to go.

My car now drives beautifully! No more rough idle, and the acceleration is so much better it's hard to believe. If it weren't for this forum, this problem could have cost me a ton of money. Thanks, everyone. However, I have a few more questions:

1) I can't get the diagnostic box to blink at me anymore, not even once, no matter how short or long I hold the button down, so I can't reset the CE light. It appears that the wiring harness has been changed, but the box was working when I got my #7 code off of it, so I'm not sure what the problem is.

2) When I turn on my headlights, the "check exterior lights" button comes on, but then goes off after about 2 minutes. I checked all the lights with my brother, and we didn't see any out. Anyone have this problem, too? Is it a loose bulb or just faulty electronics or what?

3) I'm interested in that DIY diagnostic LED tool for the other pins, but can't seem to find it in the archives. I'm probably using the wrong keywords, can someone link or tell me what its called? Thanks

4) I live in Iowa, any suggestions for summer/winter engine oil types from anyone in this type of climate?

Again, thanks for all the help, I bow down to the collective knowledge avalible on this board. Looking forward to 200k.

John