Isuzu Repair: 89 trooper rough idle when cold, mileage vehicle, high mileage

Question
Hi Daniel,

I just purchased an 89 trooper 4cyl 4wd 5spd.
Idles rough when cold, and stalls as well, until warmed up,
then it runs great up to 75 mph on the freeway !
Figured it just needed a tune up, took it in today, shop suggested to do a compression test first, o.k., they claim
that the #2, & 4 cylinder only have 25 psi ?!?! " you need a new engine around $2500 !!!! "  I've taken it to another shop that I trust a little more waiting for word from them.
Just wanted to ask you what you think the prob may be, since you seem to know a lot about Isuzu's based on your answers for some similar issues.

Thanks !
Ed

Answer
Well Ed the compression should be anywhere in the range from 150-175 per cylinder on a good engine. So Either you have some sneaky mechanics, or your engine has been around the block a few times. If it is a high, high mileage vehicle they may very well be right Ed. Let me know what you think about this and Have you had the fuel pressure checked? Choke? Starting and charging system?