I am going nuts trying to figure this out. Car starts and idles rough and loud for about 6 minutes then she smoothes out with a good idle and is quiet. This happens every day. Every mechanic I have taken her to doesn't seem to feel It's aproblem. Is this normal for a car this age. I need HHELP

does this happen on only cold starts? what are hot starts like? If you really want some good feedback (not saying that this isn't good...) post on the sl board on this website.

The cap, plugs and wires were changed three months ago. I have only put 600 miles onthe car since then. Note she starts and runs nicely when she is hot. Idles cold at 1200 rpm and rough,after about 6-8 minutes she drops down to 800 rpm.thanks

the car will automatically keep the rpm's up for a little while so the car can warm up, when the car is warm, it drops back to normal idle RPM (700 or 800).

To MPNY, Are you a Forum editor?

Correction! To MPNYE,Are you a Forum editor?

more info please...

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1999 F350 Crew-Cab with 5th Wheel Trailer Good 'ol Bass Boat (no-name..flea market special)

1992 Dodge Grand Caravan (don't laugh it has never let me down)

1987 Buick Grand National GNX (sitting right will she will be sitting for many years to come!)

1982 Buick Century V6

1986 Dodge Daytona Shelby (sold)

1968 Unimog 404

Have you checked all of the basic, ie plugs, wire, cap & rotor, correct ignition timing? If all of that is status quo, then check fuel pressure when the engine is hot & cold. Check manifold vacuum for any leaks. If you supply us with more info as requested, we can help you. Without any specific info, we can only run down the basic and take guesses. Checking the above items is not expensive and they have to be up to par in any case.

Is your car a U.S. car or a grey market car?

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1999 F350 Crew-Cab with 5th Wheel Trailer Good 'ol Bass Boat (no-name..flea market special)

1992 Dodge Grand Caravan (don't laugh it has never let me down)

1987 Buick Grand National GNX (sitting right will she will be sitting for many years to come!)

1982 Buick Century V6

1986 Dodge Daytona Shelby (sold)

1968 Unimog 404

I think the 73's were injected with D-Jetronic... I believe they updated to K-Jetronic in '77

hahaha... I'm gonna piss myself laughing at your inexperience. (where's that sarcasm smiley?)

there's no ECU on these

I have no clue what you just said.

again, you leave me in a sense of confusion. can anyone else tell me what he is trying to say? learn me somethin????? is that english??

Are you trying to be sarcastic and tell me there is an ECU in the 450SL??? I could be wrong, but I don't think I am. I just have no clue what you're trying to say.

Electronic Control Unit. I have replaced the ECU on my brother's and his girlfriend's car. I'm not stupid. I don't think there is an ECU in the 450 because I have a 450SL, it's mechanical fuel injection, and it's an old car. Don't assume I don't know what I'm talking about if you don't know anything about me.