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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Car
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Experience:  16 years of experience
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1988 Isuzu trooper: 2.6 gasoline engine fuel injected..always started

Customer Question

I have a 1988 Isuzu trooper ll 2.6 gasoline engine fuel injected. I had an '86 carburated model yrs ago.

the '88 has always started without any delay. It's always idled better in the cold wether than in the hot summer. One time I even saw gasoline coming out of one of the smaller vacumn lines - when I started pulling off lines one-by-one. I also think it runs better -when I don't have a full tank of fresh gasoline. It was getting to where it wanted to stall -out when I stop at a stop sign or when I start off after it's warmed up and been sitting a few minutes. My son took a look at it -replaced a few worn-out vaccumn lines according to the diagram under the hood and finally had to turn up the idle screw to get the car to idle at higher RPM's that took care of the stalling-out problem but now when I drive the car back fires whenever I coast down a hill with the car in 5th gear. To avoid back firing I have learned to put the car in neutral anytime I am not feeding gas with the gas pedal. When I stop or even when I just have the car in neutral the car idles up and down on its own from 1000 rpm's to 1400 rps. Like a loping
or pulsating in the idle.

I wrote to Just answer about 5-6 months ago and the mechanic told me something about the 4 cyl engine I have . He said for the most part that people end up having their mechanic remove the pump under the hood (on the drivers side front of the engine compartment and just tie off the vacumn lines that went to the pump. He felt that plugging a vacumn line or two where the pump was originally located would take care of my problem and in his reply tried to send me two illustrations showing where the pump and it's previous connections were. Problem was the two illustrations he sent just came to me as blanl black boxes -when I read his reply.
My old '86 model didn't have a pump on it when I first got it.
I had the head rebuilt on that car when it developed an idleing problem and would stall whenever I stopped at a light or stop sign. But that car never had the loping in the idle after we turned up the idle screw. It just ran at the highter idle. It finally lost power and started knocking while driving it one day -I parked- figured it was a rod knocking ?? it and still have the car hoping that one day tI will get it running again.

I really am fond of the 4 cyl, 5 spd,XXXXXtrooper ll - wish they would make another model similar. Oh yeah before I forget, the '88 tht I'm searching for answers on has almost 240K mile on it and I do change the oil and filter every 3000-4000 miles.

>>>>Would really appreciate a mechanic who's the most familiar with troubleshooting a 4 cyl. Isuzu trooper engine/idleing /vacumn ? problem.
Submitted: 6 years ago.
Category: Car
Expert:  al-mod replied 6 years ago.

Hi, I'm a Moderator here at Just Answer and will try to help you get an answer as you have been waiting for awhile. The response rate on Just Answer is usually over 95%, but sometimes questions do go un-answered. Some of the common reasons found on some questions are:

1. The question is unclear.

2. The question price you selected is low for the complexity of the question.

3. The question seems to request an answer for something that cannot be explained online.

4. And sometimes, there just may not be an Expert available who feels they have the proper experience to reply.

If you would still like to receive an answer from an Expert, just let me know, and I will do my best to find an Expert to assist you.
Customer: replied 6 years ago.

Thank You for the reply. Since you are a moderator for "Just Ask" If you could just find out why I did not receive the two illustrations the first mechanic

intended to Email me with his suggestion about disconnecting certain vacumn lines that used to go to the engine pump- to correct the problem -that would be helpful. (maybe the solution would have been to "mail" me his answer with the illustrations intact. I of course would need his ANSWER again with the illustrations. It's been so long ago, I have probably thrown away the email correspondence. I never worked on the car to try

to correct the problem- have just adapted to driving it the way it is.


Any Isuzu, former mechanic (experienced with the Isuzu Trooper ll 4 cyl. 2.6 gas engine) would have probably already had the experience of trouble shooting and correcting this problem.

The cars have been around for many years and there is quite a following even today.


Gray Trooper

Expert:  al-mod replied 6 years ago.
Hi, you can access all past question threads by clicking the My Questions button in the upper right corner of the screen. You can also use the link below:

The link to the diagram that was posted on the Expert's first reply has long since expired though.

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