Transmission Problem?

Ok, this will probably sound confusing but here goes. I truly appreciate any help. I own a 2001 Z24 2.4L with around 84k miles and I bought it used at 64k. I noticed this issue a few months ago right around the start of spring.

The issue I am having occurs when I am going least 45+ mph and in 4th gear. There are times when I want to accelerate going this speed and the accelerator pedal is very stiff and I am forced to press down hard on it. The RPMs then jump up INSTANTLY by at least 1000 and the engine/transmission screams at me for a second or two. After that the speed will increase but the tachometer continues to show the RPMs doing funny things, as the needle at times just sits there or even drops a tad bit even though I am continuously gaining speed. I cannot tell if this is an indication of the transmission going bad or if there is a fuel problem. I have also noticed that the fuel gauge has been VERY inconsistent for some reason, often jumping up and down quite a bit between stops/parking/accelerating.

I had a local mechanic take a look at the transmission fluid level as this vehicle does not have a dipstick (lame). He noticed that it was nearly 2 quarts low on transmission fluid. After filling it full I ran it a few weeks and then brought it back for him to drop the pan and change the transmission filter and add new fluid. He felt the old filter and fluid itself was pretty clean and did not notice any leaks in the transmission. Since then I have had the fuel filter and spark plugs changed, and that has not helped with this problem at all. Since I have noticed this problem I have had a dramatic decrease in fuel economy as the past 2 full tanks have barely scraped the 17 mpg mark when I was used to 28+ mpg.

I have been scouring the internet trying to find someone with a similar problem but to of no avail. Running out of options before I have to take it into the dealership where I purchased it in order for them to charge me mucho $$ :banghead:

I would do a fuel pressure test. You can get a loaner from autozone for about 160.00 refundable dollars. Tape the gage to your windshield and go for a drive, watch to see if it fluctuates. the set comes with book that gives the pressure specs for almost any vehicle known. and it comes with a variety of adapters to fit any vehicle. The fuel gage jumping up and down sounds consistent with a possible bad ground on you fuel pump circuit which could be the cause of all your problems. But then that would be to easy. Post back let us know.

check the cable? Mine went weird. Full throttle then slow. It broke. Maybe yours is binding somewhere?