Loss Of Acceleration Above 4k Rpms?

[THEogDONKEYPUNCH]

I have an automatic late 01 gt with 132000 miles. Any time I get on it, once it reaches 4k rpms and above there is a VERY obvious loss of acceleration and my rpm guage climbs much slower than usual.

Here are the things I've already done to try to resolve this issue-
new fuel pump
new fuel filter
new tps
cleaned MAF sensor
changed spark plugs

I am at a loss here guys and it's really pissing me off that I can't figure out what's going on. Torque converter maybe?

 

[Modular2v]

Sounds like the converter/tranny

 

[THEogDONKEYPUNCH]

Sounds like the converter/tranny

I was planning on camming my car anyway. Should I just go ahead and get a good converter with a stall and see if that fixes it or go ahead and get a built tranny?

 

[Modular2v]

Are you naturally aspirated???? If so, no point in buying a fully built trans

 

[THEogDONKEYPUNCH]

I am for now. I'd like boost in the future but not right now. So go ahead and save some money for a good converter? I'm getting comp cam stage 3's so what would a good converter be?

 

[squeak93]

If you have a converter problem severe enough to cause this issue you're best off rebuilding the whole trans as it likely has crap in it from the bad converter and is about to give it up as well.

I would like elsewhere if it were me.

Any codes? How did the spark plugs look when you removed them? (any smashed, oil/water soaked, fouled, burned further down then the rest?)

 

[squeak93]

OH, will the engine FREE rev above 4k while in park or N?

 

[THEogDONKEYPUNCH]

It will free rev no problem, only under load is when I have the issue. Also the spark plugs looked horrible. Pretty sure 2 of them were basically half spark plugs.

 

[squeak93]

Can you elaborate on what you mean by "Half spark plugs?" Were they burned off or smashed?

Also, If it free revs but won't under a load that can be caused by any of the issues you listed. Obviously you need air fuel and spark to get the car to move. If its having issues under a load and you KNOW your getting fuel (can test with a gauge on the schrader valve), you assume its getting air unless the MAF is unplugged, dirty or broken, the only item left is spark. I'd look at a bad coil pack or multiple ones. If you have a buddy with a car that will loan some coil packs that would be the first test to do if all other items check out.

 

[Modular2v]

It will free rev no problem, only under load is when I have the issue. Also the spark plugs looked horrible. Pretty sure 2 of them were basically half spark plugs.

This is definitely a transmission issue

 

[Modular2v]

Not sure what you mean by half spark plugs but if it was a plug issue, you would feel it buck/surging while under throttle. If it "free revs" or slips, its a transmission issue