Calling all tech's,

I have a 96 T4R, Limited, 5VZ-FE with 141,000. I purchased the truck last October, where it sat with new tire, oil, and shocks for over 7 months after the owners upgraded to a Sequoia. This truck was dealer serviced up to 95K. I purchased it with 135K. I have had no issues for 6 months, now the truck is starting to buck/miss when under load at about 1/3 throttle. This occurs mostly on the highway. I don't see any drop in RPM when this happens.

Here is what has been done so far:

New plugs installed in November
MAF Cleaned
Brand New Air Filter

None of these items have fixed the problem yet. I have seen other threads claiming that this is caused by:

Fuel Injectors
Compression problems
Plug wires
Fuel filters
O2 sensors/CC's
TPS sensors

Oddly enough, I get no CEL with this issue. So the ECU isn't even picking up any problems.

Has anyone ideas of where to go next? What the cause might certainly be? I could take shots in the dark on this, but I'd prefer some concrete logic before I start tearing into my motor.

 

When was the last time you changed plug wires? The code is not always set off by a miss. Sometimes it can miss within a given number before the computer actually pops a code and it can also partially miss where some but not all the fuel is being burned. Usually the bucking under load is an ignition problem, but it could be anything from that to fuel system, to valves, to head gasket. Any more info would help.

 

x2 like taking pics of the old spark plugs so we can see them, and if there is less coolant or the fuel pressure regulator could be malfunctioning.. Need more info!!