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 89 Trooper 2.6L - RPM stutter while driving at consistent speed.
#886926
05/22/08 04:41 AM
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Joined: May 2004
Posts: 515
OP
Rock Warrior
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Hello everyone, it's been awhile since I've been on the boards, but I've got a recent development I could use a bit of help with. I recently bought a Mazda Miata so I haven't been driving the trooper as much as usual, however recently the truck has started to develop what I would call a stutter while cruising down the freeway. It's not a misfire as far as I can tell, it's like I'm playing with the gas pedal. I have no idea on whether it could be something like the TPS, or even the transmission itself (Automatic Trans). I did recently disconnect the Power/Normal button as it broke, could this possibly cause the issue?
It's late, but I'll try to get a better diagnosis tomorrow afternoon.
Thank you for any help you can provide,
- Jim
1989 Isuzu Trooper II
- 2.6L 4ze1 Motor
- BFGoodrich 235/75/15 AT
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Re: 89 Trooper 2.6L - RPM stutter while driving at consistent speed.
[Re: thepcguy]
#886927
05/22/08 06:14 AM
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Joined: Apr 2000
Posts: 7,268
Isuzu Moderator
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I would bet it is a misfire.
I suggest the usual cap/rotor/wires and plugs, plus the fuel filter. Setting/checking timing and valve clearance is probably a good idea (not that either of those will cause a stutter, but the 2.6 just seems happier when everything is set correctly.
Beyond those things, I suggest looking at the air intake tube between the MAF and the throttle for cracks. The fuel injectors may need some kind of clean/rebuild/replace attention, if it sat long enough. Replacing the vacuum lines might be in order, depending on when it was done last and what they look like currently.
The diagnostics of a compression test may be in order. It will at least tell you how the engine is as far as the basic mechanical condition.
Other, less common, issues might be the coil or the condenser. Although, the condenser usually causes a no-start condition and the coil is generally functional or not.
Start where you like, but I would bet dollars to donuts the stutter you feel is indeed a high speed misfire.
Michael
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Re: 89 Trooper 2.6L - RPM stutter while driving at consistent speed.
[Re: mlclark]
#886928
05/22/08 12:19 PM
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Joined: May 2004
Posts: 515
OP
Rock Warrior
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I would bet it is a misfire.
I suggest the usual cap/rotor/wires and plugs, plus the fuel filter. Setting/checking timing and valve clearance is probably a good idea (not that either of those will cause a stutter, but the 2.6 just seems happier when everything is set correctly.
Beyond those things, I suggest looking at the air intake tube between the MAF and the throttle for cracks. The fuel injectors may need some kind of clean/rebuild/replace attention, if it sat long enough. Replacing the vacuum lines might be in order, depending on when it was done last and what they look like currently.
The diagnostics of a compression test may be in order. It will at least tell you how the engine is as far as the basic mechanical condition.
Other, less common, issues might be the coil or the condenser. Although, the condenser usually causes a no-start condition and the coil is generally functional or not.
Start where you like, but I would bet dollars to donuts the stutter you feel is indeed a high speed misfire.
Michael Michael, Thanks for the ideas. I should also mention that the stutter is not consistent, the truck will run just fine going 35mph, then start, then stop, as will it do it at 85mph. I'll toss in a set of wires, cap/rotor, check timing, fuel filter, etc. and see what happens. I'll also run a test to see what the on board diagnostics are showing. I'll report back with what I find. Take care, - Jim
1989 Isuzu Trooper II
- 2.6L 4ze1 Motor
- BFGoodrich 235/75/15 AT
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Re: 89 Trooper 2.6L - RPM stutter while driving at consistent speed.
[Re: thepcguy]
#886929
05/23/08 08:17 AM
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Joined: Jan 2000
Posts: 2,437
Body Damage is Cool
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Check this thread, see if the symptoms are similar: 2.6 Problem
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Re: 89 Trooper 2.6L - RPM stutter while driving at consistent speed.
[Re: lttlbddy]
#886930
05/27/08 08:48 PM
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Joined: May 2004
Posts: 515
OP
Rock Warrior
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Sorry for the delay on getting back to this issue. Problem was failing spark plug wires. I replaced them last year, but they've already gone bad. I located two wires that had started arching into each other. I replaced the wires and plugs and all is well. The problem became much more apparent after I washed my truck. The mis was much more noticeable and easier for me to figure out. Thank you for all of your help.
Now to figure out how to get this damn plug out of the block for my oil pressure sender. Stripped allen head plug....
- Jim
1989 Isuzu Trooper II
- 2.6L 4ze1 Motor
- BFGoodrich 235/75/15 AT
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