v6 3.4 wont rev above 3k

[4bangr]

digging up this thread again because I'm having this issue and maybe someone that fixed it will respond.
i just replaced the passenger side head and just like the others here, it pulls hard out of the hole (supercharged) and then hits a rev limiter at 2500 rpm.

to me, it seems throttle position related, as long as you don't go past about 20% you're fine, past that its like its starving for gas, but you can smell the gas when you pop the hood. the plugs look normal, i was sort of expecting them to be wet. No codes either.

i guess the last things for me to check are the crank position sensor and double check good timing on the belt. after reading the other posts here, and seeing how the symptom is so similar, that there is some common failure here.

 

[AntleredRuin]

Check the FPS (Fuel Pressure Regulator).
This is mounted at the back of the fuel rail (driver side if I recall).

Mine failed right after I got the T4R. It has a vacuum line that runs under the intake plenum to the intake baffle. When my FPR failed, it just dumped all the fuel into the intake baffle through that vacuum line. It smelled really strongly of gas and just fell on it's face with any throttle. I could not get it past 2500 RPM no matter how hard I tried.

I got a used OEM from eBay for $35 with shipping because it's not a common failure part. 2 years later, no issues yet.

 

[Emil1999]

I’m having the same problem, won’t rev pas 2500rpms sometimes gets to 3k, new tps, remove cat no change. No check engine light.

 

[19963.4lsr5]

I’m having the same problem, won’t rev pas 2500rpms sometimes gets to 3k, new tps, remove cat no change. No check engine light.

How old are you spark plug wires and plugs?


Sent from my iPhone using Tapatalk

 

[Emil1999]

I’m not sure, I noticed that is using a lot of fuel , in one week from full tank the needle gauge got to empty super fast.

 

[Emil1999]

SPARK PLUG Pictures

 

[Emil1999]

Spark plug