3.4L losses power under heavy load

I've got a problem in my 2000 5 speed SR5 3.4L. Normal city driving, there is no issue that I can tell, but but if I try to accelerate a little more aggressively (50% or more throttle), my engine loses acceleration power and if I try to climb a steep hill, I have to downshift to 2nd and my top speed would top out at 20MPH. When I accelerate onto a highway, I can only give it about 30% or so throttle without losing power. If I am in 3rd, and I press the gas too far, it bogs down and stops accelerating. 4th or 5th under full throttle, I start slowing down and the engine sounds labored.

List of any ideas what could be my issue?

PS. I have to run with 91 octane to keep it running better. 87 octane it rattles like crazy and there is not enough power for the highway.

 

Bump for you
Dirty maf
Clean your tb
Old plugs
The usual stuff already checked?
What have you done to it so far?

 

I cleaned the MAF since I keep getting a code for it, Still do... but it didn't effect much last time

 

No expert but i would replace fuel filter and then check cat.

 

may need to just get a remanufactured MAF sensor. They can go bad. Pull a plug and make sure you have the right plugs in there. NGK=

$6 BKR5EKB-11 NGK Spark Plug Stock # 3967

BKR5EKB-11 and Denso=

$18 K16TR11 Spark Plugs, Pack of 4

K16TR11. How long has it been since you put a new fuel filter on it? Wix about $23 OEM I don't even know. If fuel filter has been replaced recently check fuel pressure rent fuel pressure gage or buy one. You can also check if your fuel regulator is working also when checking for fuel pressure. Could also be a coil going bad. Simple things first. before you start throwing $ bills at it. PDF's attached might help you a little

 

Thanks.

I've only had this truck for 5k miles.