98 XJ still...Stumbles, Rumbles, Knocks...AHHH

I have a 98 with a 4.0 and I it has been stumbling really badly especially when it it's cold outside(below freezing) on acceleration and I first cleaned the throttle body, then I replaced the fuel pump filter regulator assembly ($360!!!!) and everyone said that it was the pump...and now it is still stumbling really bad. If it starts to stumble and I floor it, it will go, but it will just knock really badly if I don't floor it... I am a poor college kid...please help...this sucks!
Kyle

Not sure about the stumbling engine, but I would do a check on the critical engine sensors if your throttle body cleaning didn't help. But for future refrence do a little more research before paying that much for the fuel pump assembly, there are places where you can get one for a quarter of the $360 you paid for yours.

Good luck on the engine!