1988 Montero Sport 2.6L — Bogging / Loss of Power at WOT
Mechanics have been stumped. Looking for help diagnosing a persistent power issue on my 1988 Mitsubishi Montero Sport.
When driving, the engine feels increasingly bogged down as throttle increases, especially near wide-open throttle. The closer it gets to WOT, the worse the power loss becomes.
So far my mechanic has:
- Replaced the fuel filter twice
- Checked vacuum operation
- Bypassed the fuel tank with a separate fuel cell to rule out dirty fuel/sediment
- Had the engine run properly once immediately after replacing the fuel filter, but only briefly
The carburetor is currently the main suspect, but we’re trying to avoid replacing parts without being confident in the diagnosis. Has anyone dealt with this exact symptom on a Gen 1 Montero?
Are there known carburetor issues, secondary circuits, diaphragms, enrichment systems, ignition issues, or other common causes that can create this kind of bogging under heavy throttle?
We’re also looking for a factory service manual for the 1988 Montero if anyone has a lead.. Thanks!
