Motor not revving past 3k

Hey everybody, new Tacoma owner, not new to Toyotas though. Have been around Tacomas and 4Runners my whole life, never have worked on them a bunch though.
I recently purchased a 95 supercharged SR5 off of a gentleman, the truck was purchased by his father in 95 from Toyota and his father is no longer able to drive. In 1998 his dad had a 97+ TRD supercharger installed by Toyota.
Currently, the truck starts, idles, runs, etc. However, once you hit 3k (across all gears) the truck seems to be hitting a rev limiter. The truck doesn't necessarily sputter nor does it stall, it just stops revving past 3k rpm, you are forced to let off of the gas or shift into a higher gear. Has only been doing this for a bit and has not really been ran in the past year.
The nose on the supercharger was rebuilt less than 50k ago and the truck has been well maintained.
I've looked through the Forums and asked on a couple of Facebook groups, I keep getting answers and possibilities that are all over the place.
Any suggestions? Where should I start.
Thank you in advance, I appreciate and guidance and advice.

 

What year is the ECU on that engine?

 

Bad Gas and Fuel Filter if it has not caused any codes to trip do the simple first.

Rodent nest in the air in take ?

 

1995/1996 Tacomas were not able to run the TRD superchargers unless they swapped ECUs with a 1997+...has your ECU been swapped?

If a supercharger was installed on your truck without changing the ECU then that's at least part of the problem

Although if it was installed by Toyota way back then, I'm sure they addressed that...hopefully.

 

I could see Toyota techs installing the Super Charger and not Swapping ECM`s most likely the yard person did the work.

 

But if it was done way back in 98 and didn't have this issue until just recently, that makes me think they must have. I don't know if it would specifically relate the the low RPM limit though, from what I remember the issue with the early ECMs was that they couldn't adjust timing or something like that appropriately when they engine was supercharged. Someone else will have to chime in on the details of it, I just know that in order to boost a 1995.5/1996 appropriately you have to swap ECMs

Maybe the OPs truck is in limp mode due to a misfire or the like? I'm not sure what RPM limp mode stops you at but I know it's supposed to keep you from going too fast or revving too high

If that's the case, I would be curious was the check engine light code is.

 

Is it cutting out and in completely like a rev limiter or is it starving at 3k?

Does the rpm cutoff stay the same in neutral?

You could just have a broken rev limiter

 

My first thought is an ignition problem, but I know zilch about ignition on that engine.

 

I do know about the ecu not being compatible from 95 & 96 to 97-04. A good friend who live in Grass Valley, CA and builds Tacomas informed me about this ecu problem.
I asked the owner of the vehicle and he had no idea if Toyota swawpped the ecu back in 98 when they installed the supercharger. He did tell me that he recently took the truck into the shop and for some reason he thinks the certified Toyota mechanic put in a crank sensor that could of possibly been from the 95 Toyota as opposed to 97+
Long story short, I don't know if it the correct ecu. The owner stated that this problem has never happened before. The s/c has been ran perfectly fine on the truck form 1998 until just recent. The truck has also been sitting for about a year...

 

I have not picked the truck up yet, trailering it home from the coast next weekend. Good friend (Toyota nutjob) is going to look at it and diagnose it. I am just wanting to go into this with a better idea of how much this could potentially cost.
I didn't test it in neutral (should of though). Truck starts and runs fine, idles smoothly, picks up in rpm throughout all gears until you go to step on it and then throttle response cuts out at 3k rpms

 

I am a Subaru guy, I don't know much about Toyota motors. Just getting into my first Tacoma, can't wait to have some fun in it.
I guess it could be the ignition. Buddy says it could be a knock sensor.
Didn't hook up to a code reader, no check engine light...

 

I would hook up the code reader anyway, could be a pending code that hasn't triggered a light yet. Or the light could be out on the dash

 

Plugged catalytic converter? How does the exhaust feel coming out of the tailpipe? Is the cat glowing red? Checking fuel pressure is a good idea too.

 

Check it in neutral for sure. Was thinking maybe the throttle isn't opening up fully so also try reving from under the hood. Something under the gas pedal? Sometimes it's the really odd things. Best of luck

 

Plugged catalytic converters are known to cause this.

OP did you ever get this solved?

 

I had this issue once. Shop said plugged converter. Replaced it and it marginally helped at best. I threw in a new set of plugs and wires and it fixed it. Haven’t had a issue since. I had no cel light or codes at the time as well.

 

I've had the EXACT same issue for the past few months. The needle hits 3k on the dot and won't push any further. I don't have a supercharger so cross that off the list as a culprit. I'll have to try the plugs and wires as mentioned above, or something else if anyone else has solved this before.

 

I might add use a set of quality wires and denso or ngk plugs. I’ve heard the 3.4 is very finicky on ignition parts.

 

TPS maybe