1989 Isuzu Trooper II engine surge at idle?

[Al_Barrs]

On my 1989 Trooper II 4x4 the 2.6 Lt engine sometine surges about 400 to 500 RPM when I let off the accelerator. Anyone know what might cause this. The range is usually between 1300 and 1800 RPM. Thanks...Al

[kyleh200]

Originally Posted by Al_Barrs

On my 1989 Trooper II 4x4 the 2.6 Lt engine sometine surges about 400 to 500 RPM when I let off the accelerator. Anyone know what might cause this. The range is usually between 1300 and 1800 RPM. Thanks...Al

Hey Al,

I have an 88 2.6L doing the same thing. Ifound a bunch of vacuum lines unhooked on mine but cant figure out where they go. Any luck on this problem?

[Al_Barrs]

Originally Posted by kyleh200

Hey Al,

I have an 88 2.6L doing the same thing. Ifound a bunch of vacuum lines unhooked on mine but cant figure out where they go. Any luck on this problem?

Good morning Kyle;

I have read that the fuel pressure has something to do with engine surging like mine. I have driven it some at lower speed and it appears to have gone away. There is a procedure for checking and relieving the excess fuel pressure, but all I did was release the fuel filler cap and leave it loose for a tank of gas. The procedures was so complicated I didn't want to try to do the fix. I found them, I believe, In my Climer Isuze Repair and Mainteance Manual. Do you have a manual?

Good luck,
Al Barrs
Greenwood, FL

[kyleh200]

Originally Posted by Al_Barrs

Good morning Kyle;

I have read that the fuel pressure has something to do with engine surging like mine. I have driven it some at lower speed and it appears to have gone away. There is a procedure for checking and relieving the excess fuel pressure, but all I did was release the fuel filler cap and leave it loose for a tank of gas. The procedures was so complicated I didn't want to try to do the fix. I found them, I believe, In my Climer Isuze Repair and Mainteance Manual. Do you have a manual?

Good luck,
Al Barrs
Greenwood, FL

I have a Chiltons manual is all. I will look in it tonight and try your gas cap trick also. Mine surges when I let off the gas and if I put it in park after its warmed up it stays at a higher idle

[Al_Barrs]

Yes Kyle, that's when my Trooper surges...when I let off the accelerator. After my expereince I believe it may have something to do with the fuel pressure. Try driving it at 55MPH and loosen the fuel filler cap. Maybe you'll get luck like I did. Good Luck...Al

[89trooper]

did this gas cap thing do the trick? if not try this. pull the idle adjust screw(i think that is what it is called), it is on the back side of the throttle body. it is recessed a bit and takes a big flat tip screwdriver to pull out. it is likely to be black with carbon buildup. clean it off and clean out the port with carb spray real good. pop it back in and fire it up. adjust the idle in and the surge should go away. i have fixed to 88's and an 89 doing this so far.