88 Supra - Problem Holding Idle
 

I went to look at an 1988 supra(automatic) today.
No turbo, and was completely stock as far as i could tell.
The price is fairly low, it runs and starts but i didnt get to drive it.
In the driveway where I started it, i shifted from Park to Reverse to Drive and back a couple of times.
It would run alright but i had to give keep my foot on the pedal otherwise it would slowly begin to stall as the RPMs dropped.
I would like to purchase this vehicle and will be going back with a mechanic(ally inclined friend) for further inspection (check for BHGS and possibly do a compression test).

Does it fall out of idle because of the MAF?
THX for reading and any wisdom you can impart!

I think, first of all, you shold run self-diagnostic system, by connecting Te1 and E1 pins in Diagnostic box.
It may be MAF, ISCV, water temp sensor, holes in intake pipes and so on...