My girl has a 2000 Plymouth Neon. We have been putting a lot of miles on it lately since gas is $3 a gallon and my Hemi ram is an addict.

I drove the Neon for the first time the other day as she said the CEL has been going on and off for a while now. We were up in the mountains so I kinda tested what was happening by driving on flat parts and going up and down hills. What I found was the CEL comes on when going down a hill with your foot off the gas. It goes off when you get to the bottom and put your foot back on the gas (not immediately but shortly thereafter). She had the codes checked up there a while back and all they told her was it had multiple cylinder misfires. She had that problem once before and had the coil pack replaced with a nice MSD unit. While the guy was replacing it, they noticed her ex had not tightened the plugs properly and they were all loose. They fixed the plugs and then she drove it and had no problem for a while. Since then, it has gone back to having the CEL come on daily and making wierd noises and shaking when cold starting.

The car has 96k on it. I had her get the oil changed and I ordered new plugs and wires for it. I have yet to get to put my code scanner on it to see if any new codes have popped up but I will do so this week when I do the plugs and wires.

Any suggestions on what is causing this?

I am going to do all the simple maintanence on it like PCV, air filter, o2 sensors, and such but I don't want to just throw parts at it and hope for the best. Also, where is the fuel filter on this car? Is it replaceable and is there a pressure regulator that can be replaced too?

Thanks

Bob

 

if you cam get the light on the just check codes in console and then we'd have a clue

 

check for oil in the intake manifold. Not a bad job to do. oil in the intake will cause misfire

 

Ok I'll check for the oil. What causes that and what do I need to do to fix it if its there?

 

Numerous forum topics on that, but the oil is coming from the PCV system.

 

There were 2 codes showing, one was the battery disconnected within last 50 starts (I cleared it) and P0551 which is a pending fault (actively failing according to my scanner - Clear it and it comes right back if the car is acting funny) and the the book says it is a power steering pressure switch or sensor.

I looked around on the power steering pump and the rack but didn't see any wires or sensors. What am I looking for?

There were no other codes so the coil and plugs must have been the source of the misfires. I have been driving the car and noticed if you clear the fault while the car is behavin, the car is normal until it happens again. If you drive agressively the P0551 happens and then the car has issues. The P0551 always seems to trip on deceleration as stated above and when you turn the wheel the idle of the car changes and it shakes a little but only while the CEL is on.

Does this mean anything other than a bad switch/sensor?

Thanks

Bob