1993 4Runner 3VZ-E Runs Smooth Then Cuts Out Under Acceleration Before Kicking Back In
1993 Toyota 4Runner 3.0 V6 (3VZ-E) — looking for help diagnosing bucking/misfire/backfire under acceleration once warm.
The truck has improved a LOT recently, but I’m still chasing an intermittent issue. It idles pretty smooth now and cruises at steady throttle surprisingly well. The issue mainly shows up under acceleration/load.
Symptoms:
• Gets smooth consistent power for a few seconds, then suddenly cuts out/bucks like fuel or spark disappears, then kicks back in again
• Occasional backfire/misfire, especially once warm
• Slight tach fluctuation instead of perfectly steady RPM
• CEL intermittently comes on while driving
• Runs noticeably better after recent repairs, but still not fully right
Parts replaced so far:
• Distributor
• Ignition coil
• Igniter
• Spark plugs
• TPS
• Fuel injector relay
• Fuel pump
• Fuel filter
• Fuel injector connectors/pigtails
Other context:
• Toyota dealership previously found poor continuity at injector terminals
• Replacing the injector connectors made a huge improvement
• Cylinders 2/4/6 had aftermarket injectors while 1/3/5 appeared OEM. I now have 6 refurbished Denso injectors ready to install
• Mechanic also adjusted timing recently
• Exhaust is old/rusted and patched in spots
When jumping TE1/E1 in the diagnostic box I get code 14.
Before I keep throwing parts at it, what would you guys check next on a 3VZ-E with these symptoms? Curious whether this sounds more like igniter/wiring, grounds, AFM, vacuum leak, injector issue, exhaust restriction, or something else.