When mine did that it was the intermediate shaft that drives the oil pump and distributer. It slowly started cutting out at a lower and lower rpm over a couple of months until it finally died on me while driving on the highway and wouldn't re-start. The gears on the intermediate shaft and oil pump were wiped out. Hopefully that's not your problem but it sounds like you've checked most of the easy stuff. What a coincidence mine is a 1988 Sundance also

 

sounds like your timing belt is one tooth off...had the same problem - car takes off like a bat out of hell only making 6 lbs of boost and then around 4000-4500 rpm it just falls flat on its face and feels like it's hitting boost cutout.

tons of threads on here about the same problem...do a search on "timing" and "tooth" and you'll find out more info on how to check/fix the problem.

hope this helps!

 

change ur fuel filter

 

Hey Mike,

my previous van did that when the timing belt was off a tooth. wouldn't rev past about 5000 rpm without bucking like mad. I think it was advanced a tooth. If there are no other issues, otherwise it drives fine, that is your likely problem.

When the fuel pump went in my van it would just die when it got warmed up.

my 2c

 

Thanks guys.

I changed my fuel filter awhile ago, so I didn't think that'd be it.

The bucking feels sort of weird, not like it just falls flat on its face... I guess thats why I didn't think of cam timing. When it bucks sometimes it will buck once at 4k, then my engine will rev up to like 5k (as I still had my foot into it when it bucked).

I will check cam timing and if its on I'll pop the dizzy out and see if I can see the teeth on the int shaft.

Mucho gracias!