Amy - Try unplugging the oxygen sensor, when this happens again. If this
cures the problem, it's the oxygen sensor. You'll be able to make it home &
have time to get a replacement. Been there - done that - MAX
83.5 Westy ( Sunshine)
Amy Silberman wrote:

> About 4 months ago I bought a '90 Vanagon Carat and have recently
> experienced problems which the previous owners had experienced in '96.
> When going up a long hill after about 1/2 hour of driving the van
> suddenly loses power (ie. the gas is floored and I can't go above
> 40mph).  I have taken a couple of day trips and one 3 day trip from San
> Francisco to Cambria down the coast and back up.  I experienced no
> problems on this trip however is was raining and quite cold the whole
> time we were driving.  The problem first occured three weeks ago taking
> a trip into the valley where the temperatures were warmer than the usual
> SF cool.  While going up a hill there was a sound like a cork popping
> and then a great decrease in power as well as the engine sound dropping
> from its normal hum to a very low hum.  Shortly after this, black smoke
> began to come out of the tailpipe.  It was a very long 2 hour drive back
> home with the black smoke and the car topping out at about 45-50.  We
> then stopped for about 20 minutes after which the car was fine.  My
> mechanic looked at it and said he didn't know what it was.  Today I went
> out again to a warmer area with a spare computer, and of course this
> happened again, and swapping the computers didn't help.  Does anyone
> know what this problem could be or does anyone know of any materials
> other than the Bentley book that I could get on Digifant systems.
> Any suggestions or info would be greatly appreciated
> Amy S.