1992 4Runner has been bucking, stalling, and lagging on acceleration when warm!
04-08-2018, 02:30 PM
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1992 4Runner has been bucking, stalling, and lagging on acceleration when warm!
1992 4runner
manual transmission
3.0 V6
no mods
It’s an intermittent issue and I can only replicate it sometimes...
I’m getting a major hesitation on my acceleration and can’t figure out why. It seems to only happen once the truck has warmed up, or has been started back up after running for a while.
I’ll push on the gas (hard) and the 4Runner will almost stall out (this happens in neutral too) and I’ll get no power, nothing, then a burst of power as if it’s coughed something up. Usually if I give it solid gas for a bit it’ll fix the issue (almost like it’s passing something through the engine). This happens when starting the truck, when going from a stop (stalling out) and when I hammer on the gas in any gear. It idles just fine though which is weird, but does seem to jump sporadically between 800 and 1100 RPMs when it’s going through it’s rough patch. Only stalls out though when I give it gas or when starting it up after shutting down during the issue.
I’ve replaced the fuel filter and pump, spark plugs wires caps and rotor later air filter and checked for air leaks. Also cleaned my intake and MAF (thoroughly).
What do you think?
Sorry for the long post 😅
manual transmission
3.0 V6
no mods
It’s an intermittent issue and I can only replicate it sometimes...
I’m getting a major hesitation on my acceleration and can’t figure out why. It seems to only happen once the truck has warmed up, or has been started back up after running for a while.
I’ll push on the gas (hard) and the 4Runner will almost stall out (this happens in neutral too) and I’ll get no power, nothing, then a burst of power as if it’s coughed something up. Usually if I give it solid gas for a bit it’ll fix the issue (almost like it’s passing something through the engine). This happens when starting the truck, when going from a stop (stalling out) and when I hammer on the gas in any gear. It idles just fine though which is weird, but does seem to jump sporadically between 800 and 1100 RPMs when it’s going through it’s rough patch. Only stalls out though when I give it gas or when starting it up after shutting down during the issue.
I’ve replaced the fuel filter and pump, spark plugs wires caps and rotor later air filter and checked for air leaks. Also cleaned my intake and MAF (thoroughly).
What do you think?
Sorry for the long post 😅
04-08-2018, 10:58 PM
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Not even that long of a post so don't worry about apologizing.
Some things to check:
-Ignition. Pull out each plug and ground it to see if it's sparking. Grab a multi-meter and test your coil wire (I don't know the proper reading but if you get a zero in there while it's running-there you go).
-Fuel. Jump the fuel pump and make sure it works properly. You should be able to hear it whirring before start up. Check fuel filter. I doubt it's the injectors but you never know.
-Timing. Grab a timing light and see if it hits the mark properly. You may have jumped a tooth on the your timing chain/belt (I can't remember what a 3VZE uses).
Start with the big three first. If everything checks out there, dive into another area and post results for analysis and review. No use in throwing money at problems that aren't there, right? My truck exhibited very similar symptoms right before the head gasket went. Do a leak down and compression test as well for good measure. Check coolant and oil as well for signs of contamination. These steps will rule out any problems that might pop up in these systems.
Some things to check:
-Ignition. Pull out each plug and ground it to see if it's sparking. Grab a multi-meter and test your coil wire (I don't know the proper reading but if you get a zero in there while it's running-there you go).
-Fuel. Jump the fuel pump and make sure it works properly. You should be able to hear it whirring before start up. Check fuel filter. I doubt it's the injectors but you never know.
-Timing. Grab a timing light and see if it hits the mark properly. You may have jumped a tooth on the your timing chain/belt (I can't remember what a 3VZE uses).
Start with the big three first. If everything checks out there, dive into another area and post results for analysis and review. No use in throwing money at problems that aren't there, right? My truck exhibited very similar symptoms right before the head gasket went. Do a leak down and compression test as well for good measure. Check coolant and oil as well for signs of contamination. These steps will rule out any problems that might pop up in these systems.
04-09-2018, 11:03 AM
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toyodabro
I just replaced and checked (and had tested by a shop) all the plugs, fuel filter, fuel pump, timing and TPS... Also have checked for signs of blown head gasket and I'm not seeing anything that suggests it.
I can only seem to replicate the symptoms when the truck is warm and I am pressing hard on the gas.
I'm starting to lean towards O2 sensor... feels like a mixture problem because my drop in RPMs only occurs when I push on the gas (hard).
Also, check engine light isn't on (solidly). It sometimes comes on for a second then shuts off. Few minutes later, the trucks acceleration is garbage.
I just replaced and checked (and had tested by a shop) all the plugs, fuel filter, fuel pump, timing and TPS... Also have checked for signs of blown head gasket and I'm not seeing anything that suggests it.
I can only seem to replicate the symptoms when the truck is warm and I am pressing hard on the gas.
I'm starting to lean towards O2 sensor... feels like a mixture problem because my drop in RPMs only occurs when I push on the gas (hard).
Also, check engine light isn't on (solidly). It sometimes comes on for a second then shuts off. Few minutes later, the trucks acceleration is garbage.
04-09-2018, 11:14 AM
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toyodabro
I just replaced and checked (and had tested by a shop) all the plugs, fuel filter, fuel pump, timing and TPS... Also have checked for signs of blown head gasket and I'm not seeing anything that suggests it.
I can only seem to replicate the symptoms when the truck is warm and I am pressing hard on the gas.
I'm starting to lean towards O2 sensor... feels like a mixture problem because my drop in RPMs only occurs when I push on the gas (hard).
Also, check engine light isn't on (solidly). It sometimes comes on for a second then shuts off. Few minutes later, the trucks acceleration is garbage.
I just replaced and checked (and had tested by a shop) all the plugs, fuel filter, fuel pump, timing and TPS... Also have checked for signs of blown head gasket and I'm not seeing anything that suggests it.
I can only seem to replicate the symptoms when the truck is warm and I am pressing hard on the gas.
I'm starting to lean towards O2 sensor... feels like a mixture problem because my drop in RPMs only occurs when I push on the gas (hard).
Also, check engine light isn't on (solidly). It sometimes comes on for a second then shuts off. Few minutes later, the trucks acceleration is garbage.
04-09-2018, 03:02 PM
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Just my two cents, I had hesitation and pulsing throttle response with a broken fuel pressure damper. Do you have a fuel smell coming from the engine compartment? If so, check that. if not, it's probably something else like the above have mentioned.
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