i just recently did a 2.4 swap on my 97 neon everything was running fine for like about a month. But recently its been jolting at high rpm specially when im on the high way ive check everything possible and i cant find anything wrong with it no check engine lite or anything i even took it to the dealer and they didnt find anything so i really need help.

 

What injectors are you using? Cams, plugs, wires, etc.? Have you checked fuel pressure at the rail lately? And how high of an rpm are we talking about?

 

stock 2.4 injectors and i did check the fuel pressure but everything is fine and its about 2500 rpm when iot starts shacking.

 

2500 isn't really all that high... I won't even floor it below 3k rpm. Anywho...

My first guess is that there's a fuel mixture problem somewhere. Could be that one of the O2 sensors is giving a false reading making you run rich. Could be a bad injector sticking open/shut making the other cylinders run lean/rich. The TPS can be off enough to throw things out of whack without throwing a code. Without codes, tracking these things down is the suck... been there...

Could also be you got a bad tank of gas, maybe some water in it. One of the guys here (or maybe another forum I frequent) had the same issues, fixed with a can of dryout...

Best of luck!

 

If it was me I would run some Sea-Foam through it with a new tank of gas and see what you get. If that doesn't help, I would guess it's an electronic issue.

 

thanx ill try it and ill get back to you.