2.5 rough cold idle
 

When I started my car this morning, it ran rough for the first few minutes. Not a bad glow plug rough, no smoke. It would rev then shutter, rev, then shutter until it hit operating temp. What do you think???

1992 300D 2.5 Turbo 174,000 miles

Try checking the glow plugs. The 602.962 motor does have a self diagnostic on it for the glow plugs, but you can have a bad glow plug and still not have the diagnostic light be triggered.

CJ,

Thanks for the reply. I would imagine a rough idle rather than revving if it was a glow plug issue. Am I mistaken?

-Slowmoe

My gut says its not the glow plug. Sounds to me like an intermittent problem with an injector.

A few weeks ago I finally got around to running some diesel purge through the beast. It still does this silly high-low idle revving thing until it reaches operating temp. I am imagining an electrical reley, auto-choke, throttle body position sensor or something like that that may be the culprit.

Any thoughts...?

I just drove 2700 miles from Southern California to Washington state and back over the holidays.

While in snow country, my glow plug light refused to come on when I turned the key. After waiting 30 or more seconds, the car fired right up, but ran rough. The glow light also came on -- after I started the car, but went out after a minute or so. After the car warmed up, the engine smoothed out and cruised for hundreds of miles each day.

Upon my return, I discovered that the No. 4 plug was dead. New plug, problem gone.

Good luck.