So as you read in the title I have a problem that has stumped 3 mechanics. It's an '03 Dodge Neon w/ 93,000 miles, smooth running at speed until you come to a stop. It seems to only be a problem during the warmer months when temps outside are about 85. A short drive lets say 10 miles and there will not be a problem. Anything over that and in stop and go traffic and you get a jerking/shaking engine that at times will cut out all together. If you catch it in time and give a little gas you can keep it from cutting out. So far the plugs, wires, and ignition coil pack have been replaced by one mechanic. Then the idle air sensor/switch by another. Most recent the fuel injectors. Then winter came and the car ran fine, summer is approaching and its acting up again. Any ideas? It's in great shape, smooth running when not stopped, a/c works so I really can't see giving it up w/out trying to fix it.

 

A/C on or off ?


The Throttle Body plates in those are made of a plastic composite material. I have seen them warped pretty bad before and cause an idle air issue, which will make the engine die.

 

It will do it w/ the A/C on or off.

 

When they check for codes, is it empty?

 

Only evap, p0440 maybe can't remember exactly.

 

Crank sensor could be getting hot and dropping out. Many times they leave no trace and sometimes even wipe out the PCM memory in the process by shorting the 5 volt reference. I could tell much more if I had a scan tool on it, but for now that's all I have to throw out there.

 

A lot of what I have read points to the PCM saying it needs to be "reflashed" by a dealer. One of the mechanics said the reason the A/C was freezing over was due to the computer because he tapped on it and it started working again. Maybe I just need to tap it a little. I thank you for your help and suggestions on this.

 

I bet it's overcharged. I see it so many times. First thing I would look at.


We hardly ever have a flash that will make a car run that didn't before or for stalling. You need to be looking at things that "heat soak" could be causing, because your Winter was un-eventful.



I asked about AC on or off because high head pressure will drag those 4 cylinders down like you wouldn't believe. Usually because of over charging or high side pressure off the charts. If the AC high side pressure sensor is reading wrong and it doesn't cut the condenser fan on, or the fan just doesn't work, it will do exactly what you describe with the bogging down.


Unless you can duplicate the running issue by tapping the PCM, I wouldn't pull that trigger just yet. But I will tell you I see that sort of thing all the time on older PCMs.


You're welcome I'm usually not on this long but I'm wearing a cold pack tonight and staring at the PC

 

Yes I agree. The A/C was something we dealt w/ 3 yrs ago and now that you mention it he said the charge was off, added a dye and turned out to be leaking at the port. Tighten up and knock on wood its been fine since. I'm looking up this crank sensor seems to be a fairly straight forward fix. I assume that structural collar between oil pan and trans can be removed w/out too much trouble/damage?

 

Attached to that front engine mount I believe, but no big deal.