I have a '95 Dodge Neon with 150,000 miles on it. The engine has started shaking and sputtering a lot, especially at idle, but does it some while driving. It also revs itself from normal idle (600 rpm) up to about 1500-200 rpm at idle to the point that if I have it in Drive it will actually accelerate itself. Also, sometimes when I press on the gas nothing at all happens, it won't even rev. It's like I'm not even pressing the gas at all. But this does not always happen. When it does it's either coming from a complete stop or the throttle will stop working at about 20 mph. It doesn't seem like it's sticking in any gears or not going into gear, it just doesn't seem like the engine is getting any gas when I press the pedal.

It shows an OBD code of 21 (Oxygen sensor problem) but has shown that for a while. The shaking and revving/not revving started today. I don't think the O2 sensor alone will cause the gas pedal to not work, I could believe that it would cause the revving, though I could be wrong.

Any suggestions as to what might be wrong would be very helpful. Thanks!

 

I'd suggest using a throttle body cleaner, as the years of EGR gases often cause idling and acceleration issues. Replacing the 02 sensor and a tune up, (plugs wires, air element) should smooth your neons operations as well. Also, have a look at you engine mounts. If they are stock, there is a 90% chance the rubber in them is torn/ broken. If left this way for long, yout axles will be next to go.

 

look for be vacume leaks, also could be a problem with fuel injectors or TPS.

get new spark pulgs and run a fuel injector cleaner see if that helps