hello i have a used 02 neon 5 speed with 116495 miles that looks like a new car now here is the problem it starts fine idles fine revs fine in neutral no problems
when i start out it runs fine has great accleration shifts smooth and cold or warm but when im driving at 60-65 in 5th i will get like a jerking like miss but the no cel light when i down shift and the rpm goes up it will jerk more and when im going 25 in 2nd or 3rd it will jerk like mis all the time.
i have checked the sparkplugs they looked a little worn so i changed the with nkg v-power copper core gaped at .035 and no change so i bought a new set of wires and it made no change so i did a vac test and it was 19psi and did the throttle blip test and it went to -5 and quickly went to 25+ psi and the fuel pressure was i think 49 ish can't remember mu comp test was not done cause my tester was leaking cause the first time i tested it went to 240psi and i tested it again and it was 80psi and it was making phift phift phift sound like leaking air so HELP ME PLEASE

 

Those vacuum readings are interesting...
A leaking air sound could be a vacuum leak and can cause performance problems. Perhaps those readings are odd because of a leak?

 

ok i did a comp test and stone cold it was 190 190 200 205
after i let it warm up for 5 mins to 10 mins i did the test again it was
210 210 210 220 bit the 220 i think was i cranked it more then 5 times
is the good for these engines i dont know have no book

 

Does it jerk when you are doing 65 doing a solid speed or when you first press on the gas after coasting?

Could you describe it as like having a trailer attached to your car or more of a shudder?

 

when i step on it it runs great no shutter jerk nothing
when im solid 60 to 65 it feels like im tapping on the breaks real fast
same when driving 25 so i thought it was my breaks but if i push in the clutch and coast it rolls smooth or when i put in nutreal it does that only under solid load

 

If you have access to a scan tool I would hook it up and look at this specific PID.

With your engine off while looking at your TPS voltage on a scan tool slowly depress the throttle until it is fully depressed.

Chances are from what you are describing it sounds like you might have a deadspot in your TPS so it would look like a diagonal line and then all of a sudden drop off and then continue where it left off.

If you get what I'm sayin.

 

ok i talked to the ppl i got the car from and they said the clutch got replaced i thought from the car lot they got it from but i found out it was the private back yard machanic so i think its the clutch when i rev up in second to about 3500 rpm and let my foot off the gas the car starts to jerk when it slows down like they put a new clutch on a old flywheel or it misaligned or somthing what do ya think

 

Well if you ride the gear down without pressing the gas your probably going to get a little bit of jerking.

 

i dont think u understand i know you have been going down a hill and had your foot off the gas pedal and let the engine slow ya down well my car jerks like it misfireing

 

Well you're probably going to have 2 distinct types of shudders from a misfire or a transmission problem.

But if it were a clutch problem I would assume that whoever did your clutch didn't replace the pressure plate or didn't tighten down correctly and that would sound like the culprit to me. Misalignment would also be pretty easy to do without a dummy shaft.