Strange grabbing effect in a Dodge Neon

dodge
neon

#1

I’ve been having a weird problem since July of 07, and two trips to the mechanic haven’t shed any light on the mystery.



It’s a 1999 Dodge Neon Sport with about 75,000 miles. Over the years I’ve had things like the timing belt and headlamps replaced, and in 2006 I had to have some circuit panels replaced because the speedometer and odometers weren’t registering anything while I was making a 250 mile trip back and forth from my parents’ house to my college. For what we originally paid on the car, things are getting pretty expensive.



But not like this. In July of last year I noticed that the car would grab–or kick, or knock, or jump–when I reached about 60 mph on the highway.



I thought the fuel injector was probably clogged up, so I put some cleaner in the tank and went about my business. It kept doing it. So I had the injector cleaned, and nothing happened.



In January I finally got fed up and took the car in to the mechanic. They did a tune up, replaced the spark plugs and the ignition coils, and gave it back to me. Driving it home, though, it was still acting funny. In fact, it got worse. I took it back again in early April to the same place: the mechanics installed new spark plugs and ignition coils AGAIN, thinking that maybe the ones they originally fitted were defective. No dice. They gave me the car back after a week’s investigation without charging me.



And it’s getting even worse–almost to the point where I can’t drive it. I live in Oklahoma, and the weather has changed, so I don’t think it’s caused by winter or summer conditions. Instead, it seems to be related to whether or not the car is warmed up. It has a tendency to be very bad after I drive the car somewhere, but when I’m driving home it isn’t as bad.



Here’s a better description of the problem: I don’t lose power when the weird kicking feeling happens–none of the instrument gauges change at all. There isn’t any sound accompanying it, either. It feels like I’m going over pot holes in the road even on new blacktop surfaces, or like some source of power isn’t getting to a part of the car. But I’ve had all the electrical parts changed, and the fuel injector is clean.



I’m going to be attending graduate school in the fall and need to be able to drive a car on the highway without feeling like it’s about to fall apart. Does anyone have any idea what could be wrong? And should I get a different car, or try to have this thing fixed?


#2

“Dead Head Pressure
This checks the maximum output pressure of the fuel pump. With the return line pinched shut, the pump should produce two times its normal operating pressure at idle. If the pressure rating does not go up with the return line blocked, the pump may not be able to deliver enough fuel at higher engine speeds. Possible causes include a worn pump, low voltage at the pump, a plugged fuel filter or inlet sock in the tank, an obstructed fuel line or almost empty fuel tank.”
http://www.aa1car.com/library/2003/us60324.htm

The link above takes you to a page where they outline how to detect issues with the fuel system. Hope it helps.


#3

Your description is still rather vague. Does this happen only at highway speed? Is it relieved if you slow down? If you shift into neutral while it is occurring does the effect remain or does it stop? I’m thinking restricted exhaust but I need more information.


#4

It’s at its most noticeable at 60mph but I have felt it at about 40, though that is rare.

I have not tried putting the car into neutral while going at highway speeds, but I do know that the effect will stop if I accelerate, remove my foot from the foot feed, or brake. It only does it if I’m going at a constant rate.


#5

I’m taking the car in again next Wednesday and have asked them to take a look at the fuel system and maybe flush the fuel line. Thanks–that article sounds a lot like what I’m getting.


#6

Your further information, that the effect stops when you accelerate, tends to rule out a fuel problem. Do NOT ask for a fuel system flush at this point. There is no clear indication your problem that it will help.

I cannot even be certain your car’s problem is engine-related. The description is still vague, but it may even be a tire problem or a suspension problem. You haven’t even told us whether the effect seems to affect the front or rear of the car. What you really need to do is get a mechanically knowledgeable person to drive your car for a while on the highway. Let him actually feel the effect. He should come a lot closer to the truth than the mechanics in the shop who clearly are just guessing.

Good luck. Don’t give up on this. You have a good little car.


#7

You need to drop by a local AutoZone, O’Reillys, etc. and have them scan the car. They will do this for you free and it only takes a few minutes.
When someone is replacing coil packs and possibly the spark plugs only a few months after doing so then this kind of reeks of guesswork.

Post any codes they give you back here for discussion. Do not expect the parts house guys to decipher the results; this is not their job at all.

Without knowing if there is any codes present, some reasonably wild guesses could be an intermittent fuel pump failure (when was the filter last changed?), an automatic shut-down relay hiccupping a bit, or possibly a worn CV joint that is trying to bind at times. Hope some of that helps.


#8

I’m sorry, I don’t mean to be so vague–but your further questioning does help me to remember specificities to tell mechanics in the future, so thank you for that. I don’t anticipate an immediate answer, so if I’m leaving anything out be sure to let me know.

It has no specific location that I’m able to tell. It shakes and rocks the entire car for split seconds when it’s doing it. Like I said, it’s as if you’re going over bumps in the road, but it’s sporadic.

I should also mention that it’s random and has no pattern–just knocking and shaking when I reach 60 mph.


#9

They were the ones who had replaced the spark plugs and coil packs to begin with–they wanted to see if maybe the ones they had originally installed were defective. I think they scanned the car at the shop anyway; I know for a fact they did a tune up and couldn’t find anything wrong.


#10
Get the actual codes they found (Like P0123) and post them here.  The codes never say something like replace spark plugs, but they may indicate a misfire on plug #3 type of thing.  With that information someone here may be able to figure out why the computer is sensing a misfire on plug #3.  It does not even mean there is a misfire, but only that the computer is sensing something.

#11

I took it to the dealership yesterday and they discovered the actual problem, so it is fixed now.

It was the metal plate hooked up to the electricity controlling part of the foot feed. Apparently the connection was spotty, so they had to replace it.

I honestly thought it was a fuel problem, but for now, it’s nice and healthy again. Thanks for all the responses and I hope this topic helps someone in the future.


#12

It was the metal plate hooked up to the electricity controlling part of the foot feed.

You must have misunderstood or they were giving you a line of bull. This is, quite frankly, gibberish. Foot feed?!?! That’s an ancient slang term for accelerator pedal.


#13

Nah, that’s what my dad’s been calling it, and he’s ancient, so everything just gets repeated.

I’m not a mechanic. All I know is that the car is working again. So… the point is a bit moot.