Acceleration issue

I have a 2002 taco with a 2.4 and a manual trans. If I put it in 4th or 5th gear it slows me to 60 (floored, off gas, and anywhere in between). I have done plugs, coils, has two cats that are less than 5000 miles old. I am stumped and cannot figure this out. It has no codes either to help. Please help

 

Engine rpm does not change either so it is not a slipping clutch

 

What’s the mileage on your truck?

 

About 180k

 

Assuming that’s driving on flat ground, you’re definitely lacking power. I would start with a compression test (free auto zone rental) to get a general idea of the health of your motor.

 

I’ll get one tonight, but why would that only affect 4th and 5th gear? And yes it’s flat ground

 

My thoughts on this, are that you might have a power output issue. If the engine isn’t producing the HP it was designed for, it will not do well in higher gears.

It would also be good to consider checking other potential power robbing problems. A dirty/restrictive air filter, dirty mass air flow sensor.

How does the truck run at cold startup?

 

If it’s lacking power, it’s affecting every gear, it just becomes more noticeable in 4th and 5th because you have less mechanical advantage in those gears.

 

It starts and idles with no issues, air filter is brand new, maf just got cleaned. Installing a fuel filter tonight if all goes well tonight

 

Compression is 130 psi across all cylinders at 4600 asl. Give or take 1 psi

 

Fuel filter replaced with same issue, motor just seems to load up and bog. I’m so confused

 

Four ingredients to power: Pressure, Oxygen, Fuel and Spark.

• You checked Pressure so you can check that off.
• Air is probably fine unless you have a rag stuffed in the intake somewhere for some reason.
• Fuel filter is good - what about fuel pressure? Is the pump working properly?
  
• Recheck plugs and coils?

If it's nothing here, sounds like it could be a timing issue.

 

Tested coils and plugs all tested good. Coils sent good spark through test light and plug

 

I will try to double check timing tomorrow but that should be fine as the motor has never been opened. It even has the oem valve cover gasket

 

130 psi is just a hair above the Toyota minimum comp spec for the 2RZ. If anything, and in addition to what ret42 mentioned (timing…or chain slack), your motor could also be a bit tired.

 

I did the the test cold with throttle plate closed like an idiot so I expect it’s actually a good bit higher

 

I am still waiting on the new valve cover gasket to check timing but I pulled cats to check and see if one was clogged and they were perfect looking almost brand new. Just furthering my confusion