Hello and thanks for reading. I was driving my '94 850T yesterday and went to accelerate and the car wouldn't go. The RPM's actually dropped for a few seconds. Later on down the road the same thing happened again. I gave the car gas and it acted as if it was going to quit running. Luckily, I made it to the repair shop. The mechanic said all the spark plugs were fouled and black in color. I just changed them about five months ago so I thought that was very strange. The mechanic also said it was putting out black smoke from the exhaust. I've never had this type of trouble with this car before. Any thoughts as to what is going on??
Thanks!

Check the hoses coming from your turbo to the intercooler and from the intercooler to the throttle body. One may be split/cracked/leaking. If you get on the throttle it will blow air out.

This air has been metered by the AMM and the ECU will inject fuel for this amount of air.. But becuase some (or a lot) of the air has leaked away it will be injecting too much and it goes super-rich.

Relatively common problem on older turbo cars as the heat and oil vapours from the turbo slowly deteriorate the hoses from the inside out.

Bye, Arno.

What plugs did you use? Maybe they were the wrong heat range and fouled.
I use OEM and have had to be careful that I get the plugs for the turbo
engines and not the ones for the normally aspirated engine.

I don't think a bit of black smoke is too unuseual. Every late model Volvo
I have seen has a dark, soot stained exhaust. They seem to run a bit rich.

I don't agree with that. My 97 850R has never done that. I have had it since new. I have also owned a 94 base 850 from new and never had that problem.

Is it possible that you obtained a used car and the previous owner didn't keep up the car well? I maybe wrong, but I have never been privy to this type of problem--knock on wood.