engine shut down on way home.Please help!
 

On way home from work my engine shut down. I was driving along and suddenly I noticed a loss of power. My speed dropped from 60 down to 50 and then down all the way until the engine shut down. When I tried to restart it, it was hard to start. It finally started and then when I turned to go into my driveway it shut off again. I went to the station to fill up with fresh diesel and I put an entire bottle of redline in tank. The car started and ran fine for about 5 miles then it started to drop acceleration again. What is going on here. I don't see anything wrong when I look under the hood. The car has just had it's 100,000 mile service at my independent dealer and he changed all filters, oil, adjusted valves and all the things required in a 100,000 mile service. The car is a 1979 300cd with 102,000 miles on it. I did notice that since the service, I seem to have more power and the idle seems to be a little higher. I have had this car for 3 years and have had no problems until this incident. Please help as I am now afraid to drive this wonderful machine because I don't want to make matters worse. I start the car every day and let it idle for 30 minutes, but it doesn't seem to idle as quietly as usual after it reaches ambient temp. Thanks to all in advance.

I'd have the mechanic re-check the valves. Were the fuel filters changed? Also try removing you fuel cap as soon as this happens and see if any vacuum is built up. Sounds like a fuel delivery problem.

Also might he have introduced air into the fuel system if he changed the filters? Not sure about how this affects the engine, just know it's not a good thing.

Rmmagow,
Yes, both fuel filters were changed. Are you saying remove the fuel cap when the car stalls and shut down? Can you specify "fuel delivery problem" Thanks for your quick response.

Sometimes the vent for the fuel tank gets clogged by spiders, wasp, mud, etc. When this happens what you discribe happens. Drive with the fuel tank cap off and seee if this cures the problem, if so crawl under car with coat hanger and snake out the overflow tube. :D

Bad fuel??
 

I did buy fuel from a low volume pump the day before this incident. I usually buy it from a high volume truck stop. Does my symptoms sound like a bad fuel problem?

Thanks old navy. I am a novice here, can you describe where the overflow tube is? Sorry.

It should be near the right rear wheel area and is just a rubber tube.

Old Navy,
Thanks a bunch!! I just cleaned out the overflow tube. I went up about six inches. I got out some black debris or something. I didn't want to take a chance of puncturing anything. Let's see what happens. I will keep you informed. By the way, I just drove the car about 6 or 7 miles and it ran fine, (before I cleaned out the overflow tube.) but I still think the car should idle quieter than it is. Thanks again.

When that vent gets clogged it causes a vacuum in the tank, and it will kill the engine fastest when the tank is near full then if near empty. More air in the tank sort of thing. Also another sign is when it's fine after it sit awhile. The tank will not hold a vacuum to long, so after it sits a couple hours it may start and run fine a short distance. If you remove the fuel cap and hear a hiss then put the cap back on you will drive quite a ways before you start starving for fuel comparied to maybe just letting it sit for a couple hours.

Hope this fixes your problem. I not sure about your car but you may be able to remove the hose from the tank by going through your trunk, that way getting it really cleaned out.

Did the mechanic install a clear pre-filter? If so, look for anything that would indicate dirty fuel, the fact that you filled the car at a low volume place might indicate dirty fuel, that would give symptoms of stalling.
Another possibility (although remote) is if the supply and return pipes were swapped accidentally, then at a low tank you will draw air into the IP.
Oh yes, why do you idle it fo r 30 mins? The car should take off and run from initial start unless its REAL cold.

yes there was a pre-filter installed. The fuel in the pre-filter looks pretty clear. I let it idle for 30 minutes to see if it is gonna cut off as it does when I ride down the road. By the way I have driven the car today at least 20 miles and everything seems fine. I will keep everyone posted. Thanks for all the advice.

OK understood re: idling time.
THe clear prefilters are good for examining the sate of fuel, a small flashlight is sometimes helpful to illuminate the filter well.
Normally plugged filters will not cause an engine to die but will prevent the engine from running up to any meaningful speed.
I have had a secondary filter (spin-on) plug up and the engine runs very rough at idle yet would hardly run down the road over 20 MPH. Dirty fuel was the cause. I try to remember that event and carry a spare filter with me on any trips away from home. Rubber gloves come in handy too, the nitrile ones, and have a place in the trunk as well.

I had basically the same thing happen on my '81 and it was the tank screen blinded over. I posted a picture of it around here somewhere.