02 neon, 2.0L 4cyl, was driving on the highway when i noticed that i couldnt get higher than about 110 km/h or about 68mph. about 10minutes later i lost power in 4th, and was driving at 4000rpm in 3rd to attempt somwhat highway speed, as soon asi hit a light i was no longer able to go past about 2500rmp in 2nd doing no more than 30km/h / 20mph managedto limp it home but about a block out i coulnt get past 2000 rpm in first and i didnt have enough guts to climb a 1% grade, for a while it was idling fine, but the idle became choppy, and if you try to rev past 2500 rpm the engine chokes and drops to about 300(three hundred)rpm, there are codes showing, 0420, 0300, 0302, 0171, lvls above catalytic threshold, random misfire, cyl No. 2 misfire, and lean mixture respectively, plugs and wires just replaced, so not sure if 300 and 302 will clear up, (420,300,302 have been on there previously to the incident)

thoughts and comments greatly appreciated

 

Ok you just changed plugs and wires. So clear your codes and then try and restart.

The P0300 and P0302 are misfires as you know and P0171 is a lean code from the misfires not allowing the engine to use up the available oxygen.

The one that concerns me is the first one. Catalyst Efficiency. Now that is a problem. If the car will not stay running after resetting the codes then unbolt your cat from the header and see if it will run then. If so you melted/plugged a cat.

 

k will do

 

update:

pulled it off and it has no effect on the engine preformance, as soon as i crank the engine it is running rough, (about 400 rpm) and not a constant run, (droppes to about 200 rpm and almost stalls intill it recovers to about 500 rpm) this cycles about once a second, havent cleared codes yet, initial thought was that it was the fuel pressure regulator, but with it running at about 50psi (on position) to 60psi (idle) i believe that this is normal

 

How many miles?

 

about 87000 mi

 

another update:

car will now not catch, will crank but not start, maybe 1 in about 10 time it will catch, and still the 400-200 rmp rough idle

 

sorta sounds like your timing belt has been slipping off, at least that would explain the grandual loss of power [sm=confused06.gif]

 

no compression loss in a interfering head rules out timing belt slipping,

 

didn't know you checked compression...