Any hissing noises when you take the petrol cap off? These old heaps have a habit of getting a vacuum in the tank due to the breather system. I guess if the vacuum gets bad enough it'd cause fuel flow issues.

Just a thought as disturbing the cap seems to have made a difference.

Another thought is pickup filters blocked in the tank giving similar problems & filling up washed some dirt off the filters till the pump sucked it back again.

 

Soooo a little update, I had the fuel filter replaced, and now my P0174 code is now gone. However, I still have a stumbling idle. When either gently accelerating or staying at constant speed, it will still stumble, but if I really put my foot into it, it accelerates fabulously. Any suggestions?

 

The car is 20 years old I think that's normal for now later check your spark plugs and their seal it might leak oil causing misfire get iridium ngk or platinum Bosch I tried all denso spark plugs it just not for our engine
Get 4 inch kn air filter get rid of the air box it chock the engine I had engine vibration at 40 Miles I removed the air box and just installed 4 inch kn air filter it breath better now

 

Silverjag.....did you use any kind of heat shield to surround the K&N in the engine bay?

 

Unfortunately no

 

I would check for leaks around Bank Two: VVT seal, O-ring on dip stick . . . clean the throttle bore and plate; check for leaks around throttle fittings; take up slack in accelerator cable; make sure no leaks in air tube. How dirty is the air filter?