Stalling problem.

My Trooper now makes me outrageous. It developed the following
problems: (1) the engine stalls when I shift it from P to R or when my
foot is off gas pedal. (2) when the engine speed reach 3000 rpm, CEL
shows up, (3) after that, the engine idle speed stays at 2000 rpm level
and the stall problem disappears. (4) when I disconnect battery cable
and reinstall it, CEL become off and the idle speed comes back to
normal. But the problem (1) happens again and new cycle begins.

I sent the car to the Bill Stillwell Isuzu in Downers Grove, IL and
they told me I need a new fuel pump. Before I send the car back there
again, they went out of business. So I have drive 20 miles to a Isuzu
dealer at Orland Park, IL. This time, they gave me a even longer list:
(1) Fuel pressure regulator
(2) Distributor
(3) EGR service
(4) tune up
(5) throttle service
(6) Injector service
The total quote is $1290 plus tax. Ironically, I just had the 90K
service and got new spark plugs and fuel injector serviced 3 months
ago. I think maybe I should seek second (or third) opinion.

My fellow Trooper fans, do you guys have any idea what is the real
cause of the problem?

is a 99 year model S. It keeps bugging me for a while. The problem
began last spring, it was the CEL. At that time nothing else was wrong.
I visited my local ISUZU deal for 3 or 4 times. First they changed
Intake Manifest gasket. But the CEL came out the next day, later they
asked me to dry better gas, so I tried any brand I can find in Chicago,
later drive to Indiana to buy gas. But the problem was still there. The
last time I visited them, they asked me to change fuel filter and fuel
pump. I changed fuel filter. When I made my decision to change the fuel
pump (they asked for $900), they went out of business. So I have to
find another dealer 20 miles away. This time the sticker shock is even
bigger.

So far, the intake manifest gasket was changed twice (at 20K and 80K).
I also had 90K service at my local mechanic. they also changed spark
plugs (they claim they are platinum) and serviced fuel injector).

According to Edmunds.com, the trade in value of my car is about $4000.
Yeah, I am considering get rid of this car. I don't think it is wise
to through in $1000 for the repair that cannot guaranty solving the
problem. But my wife had a bumper scratch accident with the Trooper
last winter, I believe, the trade-in value I get should be less than
that. We just got a Toyota Sienna in December. Now my wife tries to
persuade to get a Camry. As you know, Trooper owners are the people who
don't want to be mainstream. But after all these troubles with this
Trooper, I have to think it twice before I get a new car.