First things first... I've done my research and can't find an answer/diagnosis. That's why I'm posting.

It starts fine and runs normal til it warms up all the way. Then it starts making a thump thump noise like a misfire or something out of the exhaust... Don't say anything about having no cat... that's ridiculous. I don't have an o2 sensor on or after the cat so I removed it and it ran fine. you don't need a cat.

Anyway, thump thuimp noise and the whole body is shaking on and off from the motor. plus the rpm needle goes up and down slieghtly below the 800 line or whatever the line below 1000 is... It just seems to be wanting to die but never does and lacks power.

some quick info:

-spark plugs changed recently
-new TPS, cleaned IAC, and throwing no other sensor codes
-Keep getting a small EVAP leak code but it goes away after a while
-Intake cleaned new cold air ect.
-tried staring fluid everywhere.... never seems to be leaking anywhere
- I tested vaccum...seems to be fine plus that would raise the idle anyway not lower it
-I cleaned the injectors directly through the fuel rail with 3m inj. cleaner twice already... doesn't seem to make a difference expect it doesn't hesitate accelerating anymore. Guess it cleaned one or two injectors..
-and a bunch of other shiit I'm forgetting to mention

Idk what to do... about to bring it to a mech. if I can't figure this out.

Please ask me questions about what I've done or things I've replaced and help me diagnos this annoying POS prob.

 

"I don't have an o2 sensor on or after the cat so I removed it and it ran fine."

Define "fine", it ran like crap but not bad enough to notice? Only way to have a proper air/fuel ratio in closed loop is with an O2 sensor. Or dump the F.I. and run a carb.