Dodge Neon

[jeepit]

Having a problem with Dodge Neon, single oh cam, 5 speed. When driving in 4th gear and taking foot off throttle it will slow down suddenly, as opposed to normal slow down. You then need to downshift to 3rd at which point it will seem to want to stall and sometimes will backfire. It seems to want to surge under a steady throttle application. Any thoughts as to what is wrong??

 

[mopars1]

If I had to guess it would be low fuel pressure. You don't state how the engine runs otherwise as in all the normal power if you floorboard the go pedal. It should not be a terrible problem to solve. Something basic in my opinion. Also you didn't state if the check engine light is on or not. If it isn't then I will stick with the low fuel pressure.

 

[jeepit]

Runs normal otherwise. Check engine lite had been on. I had the code read and it indicated an upstream o2 sensor which i did replace. I thought that this would solve problem, but it did not.

 

[nickleinonen]

if you can, rig up an exhaust back pressure gauge and plug it in where an o2 sensor would go, and measure the pressure... 5psi max iirc...

 

[Lodi]

Could be a partially plugged catalytic converter. Had friends that spent hundreds of dollars on repairs and never had the cat checked... ... ..... Phil

 

[mopars1]

I don't completely disagree with the catalytic converter thought with the exception that if the exhaust is starting to plug up the performance would be degraded at wide open throttle and this does not seem to be the case. It very well could be the downstream oxygen sensor getting lazy but not setting a code. This also could have caused the code setting for the upstream oxygen sensor not keeping the intended tolerance between the two.

 

[jeepit]

Found it. It was a vacuum leak. I plugged it for the time being. Seems to run well again, has more power too! Thanx for all the suggestions guys.

 

[Lodi]

Great ! Glad it was nothing major. Oo.