RPM's randomly shooting up then drops to normal while driving.
I'm not a very car savey guy. I have a 2000 V6 Mustang that's more or less run great for years. was my first car and have been driving it for the past 14 years and only just a month ago hot 100k miles. recently Ive been having a ton of issues though. the latest repair was the fuel pump. the original was dying and my car would constantly stall out as the pump overheated. I finally had a new pump installed and the car ran normal for about a week then suddenly I had a new problem. It feel like it usually takes a second for the engine to fire up after starting the ignition if its been sitting for a day or 2. it no longer stalls on me but as I drive it feels like i'm hitting a wall of jelly. the RPM's shoot up from about 1.5k to 3k rpm and hangs there for a few seconds before dropping back. It randomly does this as I drive sometimes frequently and sometimes not. my transmission has a leak and I suspected a bad tranny but the fluid seems fine, not burnt or anything and I replace it as needed. I do have a check engine engine light on and when I had it read they gave me a giant list of what it could be (all fuel system related). I've changed the oil, fuel filter and spark plugs just prior to the new fuel pump. I know my best bet is to take it to a shop but money is very very tight right now so I'm wondering if anyone here can possibly point me to any simple issues it may be. I see a lot on the net about RPM's dropping and cars stalling out with fuel system issues but not much about the issue I'm having.