Hi im dustin i just recently got a 2005 dodge neon se with a 2.0 4cyl was running fine when i got it but just recently it started bogging down and jumping when touching/leting off the gas i have change-

plugs
wires
throttle position sensor
map sensor
cam shaft sensor
throttle cable both
IAC sensor

i reset the cpu and my engine light went off for about an hour then on my way to work it came back on and while driving started jumping around 30-40 miles per hour and when i let off the gas while im driving it jumps as well and now when i shift from park to drive it jumps but only when it warms up a little bit.

i'v tried every thing i can think of there isn't any other codes comeing up other than the gas cap starts with a U so please help me figure this out thanks

 

If it jumps around, and bogs, start looking for a vacuum leak IMO. Not only the vacuum lines, but the accrodian-tube that connects the throttle bottle to the intake manifold. The folds can develop cracks, and subsequently, a strong leak.

A "U" code has nothing to do with a gas cap though...if I'm understanding that part correctly. That's some kind of communication error in the vehicle's electronics, which will cause a problem too. What are the codes exactly?

 

i can't remember exactly what the U codes were i looked them up online and 1 U code said lost connection to cluster in which i do believe i fixed when i put the radio wiring harness back on and the other i looked up said could be something with the gas cap not on tight or something like that then i had 2 P codes one for the map and one for the throttle sensors.

the car for the most parts seems to be doing ok when its cold (not always) and does most of the jumping between 25-40 mph's and when im driving and let off the gas pedal it jumps im gonna check for vacume leaks but i can't seem to find any.

now there is one of the throttle cables that has the circle metal peace with the vacume hose and the wiring harness attached i'v put 2 dif ones on the car (from junk yard) idk if that has any thing to do with it. i still drive this car every single day i have no choice but i gotta get it fixed asap its driving me nuts im very mechanically inclined and im stumped

 

these are the codes i had i think

U0155-NO CLUSTER BUS MESSAGE
U110C-NO FUEL LEVEL BUS MESSAGE

 

i forgot to mention my tachometer and my speedometer sometimes just stop for a minute and then work again when i press the gas not always but it does happen and the rpms go crazy when it starts jumping around

 

Have you checked the actual wiring for those sensors that you had codes for, or checked for proper voltage?

 

check all the wires and hoses spray some wd see when it starts to jump thats where the problem will be, Shouldn't be that hard

 

ya im bout to do that now i'll let you know thanks

 

i havn't checked voltage i don't have the voltage meter but im gonna check the harnesses

 

ok so i checked for vacume leaks and didn't find anything i checked for wires touching/bare and found a few got the wires all fixed up and taped and made sure the tbp sensor was on right and reset the engine light

i started the car and no engine light ran ok but when i gave it gas it seemed as if it was getting to much air then i put it in drive and back to neutral the engine light came back on and every time I put it in drive it jumps even if its fro neutral to drive it jumps pretty hard to