I have a 1997 Neon Stock. I just purchased it from a co-worker.
I replaced the starter. It was dead shorted.
Then the garage changed the alternator. said it wasn't putting out any juice.
OK.

When I bought the car it seemed to run great. On the highway I could feel an occassional stumble.
Randomly I would try to start the car and it would start, rev up like normal then come back down and idle real rough. If I touched the fuel it would bog out and die like it was to lean. I could usually try to start it 2 or 3 times then it would start like normal and run well.

On the freeway I can feel the stumble alot more now constanlty.
Now after driving about 20 minutes at 100kms/h(60mph) the car seems to become plugged up. it stumbles like crazy then dies.
If i restart it it will spit and sputter then stall.

I got it rolling down a hill and got up to speed in second gear and it took off.
if I let the engine come down below 3000 rpm it would start to "Plug up" and die.
I pulled back to second and it would run along for 4 or 5 seconds then start to accelerate again. I ran it up to 140km/h then shifted into drive . it took the gear and kept going. if I slowed down at all it would start to become sluggish and die.

I could not slow down without having the engine stall or stumble to death.

At first I felt it was running lean so I thought fuel filter or pump.
Then today when it would run great at high rpm it ruled out no fuel.

When the engine is cool it will start again and run good for anothr 20 minutes.

These are my thoughts

- Plugged catalytic converter
- dirty IAC
- Fuel pump/filter
- coils breaking down ?

Could anyone give me some opinions on this. I am an old school back yard mechanic. I have build and repaired many, many carbed engines and this vehicle is my first attempt at having a fuel injected machine.

I'm a software developer and hardware specialist. I look forward to getting deep and dirty with this new engine stuff.
I'de love to build a kewl street machine out of this little shoe box.

Any help would be muchly appreciated.

Dave

BTW this is a multi point injected enjine, fuel rail on top in front (if that helps anything)

 

IAC cleaning is cheap and easy, great place to start.

Copper plugs only. Platinums are death to wasted spark DIS cars like ours. The coilpacks can be an issue, but that's become pretty rare. You can pull the coilpack off and take it in to a parts store for testing. Don't forget wires. Regular stock replacements are fine. If you feel the need for an "upgrade", stick with MSD, Moroso, Mopar, Magnecor, or Crane.

Fuel filter is highly unlikely. It's a tiny lifetime unit that's part of the regulator assembly. I've never heard of one of these clogging up. The fuel pump is always a possibility, but if you are getting ~49 psi at the fuel rail, it's probably good. If you do need to replace it (intermittent short, whatever), the Walbro 255 lph upgrade is cheaper than any stock replacement you'll find, and bolts right in with no other modifications needed. Modern Performance, Howell Automotive, and e-bay amost always have them for $110 or so.

The cat should last well over 100k miles. Think mine made it about 180k miles before falling apart. The downstream sensor should pick up on that though, and you'd get a CEL for it, usually after a longer freeway drive (60-70 miles+).

If you have a SOHC, the timing belt can skip a tooth without tripping the CEL. If the car is anywhere near 105k miles and has not had the timing belt and water pump replaced yet, get it done... Upgrading to the new style MLS head gasket would be a good idea, if that hasn't been done already.

Tranny might need a tune-up. Though I'm not familiar at all with the autos and how they behave, etc.

Best of luck!

 

i had had the exact problem you stated above, it would get bad on the highway, i thought it was water in my gas (cause i had that problem before) but it was the fuel pump, so we changed it and the filter. problem solved, good luck!

 

Mystery solved.

'The cat should last well over 100k miles. Think mine made it about 180k miles before falling apart. The downstream sensor should pick up on that though, and you'd get a CEL for it, usually after a longer freeway drive (60-70 miles+).'

After 20 minutes of driving the cat would become so backed up with pressure the system couldn't continue to run right.

The clues.
I had an anoyying exhaust leak near the manifold. (To much backpressure)
Stalling after 20 minute drives on Highway ( built up heat and pressure)
Sizzling cat converter.

replaced cat and now it works much better.