Stalling at over 40mph

[leie]

My dad's car has a terrible stalling problem. It's a 1993 SE with a 2.3 V6 engine, 147,000 miles.

It's a bit different than other problems that I've heard of. I'm guessing now that it could be a fuel pump problem, but I'd like to hear advice from someone who actually knows a thing or two. About two years ago my dad's car began stalling every few months. He doesn't drive it very often, in fact he's only put 23,000 miles on it since buying it five years ago. We finally figured that when stopping from a speed of over 50mph the car would violently shake and then die. It started happening more and more often and now it seems to happen everytime it reaches a speed over 40. He gave up driving on freeways.

He's spent close to $1000 at various mechanics, they couldn't figure out what was wrong with it and even tried driving it and it never would do it when they had it. I think he just chose bad mechanics. Anyone have this problem and were able to fix it? I've read various things of compression checks, oxygen sensors, etc.

[rixGAphx]

Firstly, it's not a 2.3 V6.
It's either a 2.3 inline 4 cyl; or,
A 3.3 V-6.

Secondly, It's a 14 year old car, with *prolly* nearly all-original stuff (you didn't mention major replacements, nor did you mention total milage, nor did you mention the type of tranny).
The problem could be numerous single things (including fuel pump, or catalytic converter) or numerous combinations of small things.

Nothing specific comes to mind for this 'automatic speed limiting condition' other than FP or cat.
An FP is about $400 installed, a cat is ~$250 installed.

If the engine is the 4-cyl, it could have timing chain issues that show up when the engine reaches higher rpms.
Big $$$ to go into that part of the 4-cyl.

The V-6 is only an auto tranny.
The 4-cyl came with auto and manual.
Frankly, what you describe seems like it might be a clutch-related problem on a manual tranny.

We don't know what these mechanics did for $1000.
Certainly they replaced SOME things (plugs, wires, filters?).
Have you checked the computer's codes? I'm sure the mechanics did, but it would be nice to know what the car's computer thinks might be wrong.

You say he rarely drives it.
Modern gasolines don't like to sit in the tank for very long. He may be driving on 2-yr old gasoline, which is just plain crap.
Every spring when I fire-up the mower, if I didn't drain the tank in the fall then I have to throw-out the old tank of gas because it has picked-up water from the winter air.
If the gas level is low in the tank, say less than a 1/4 tank, fill the thing with Premium and add a couple bottels of name-brand off-the-shelf Fuel System cleaner from the auto parts store. I like Prestone and Valvoline brands for car chemicals.

The Blue Book value of the car, if in otherwise very good condition, is only ~$1100US with a running engine. As-is, you'd only get about $700 for it.
Only you and your dad can decide if any more money spent is worthwhile.

Finally, there are very few engine-related problems that are vehicle-speed-determinated.
Usually, it's the speed of the ENGINE (RPM's) that give an indication of power loss at a certain speed.
For instance, a badly-running engine might begin to shake/stumble at 4000 rpm (which would be ~15 mph in 1st gear, but ~80 mph in 4th gear).
So, the fact that you've identified a highway condition above 40 mph (~2000 rpm in 4th) confuses me.

You and your dad do, indeed, have a puzzlement on your hands.
I don't know if the above ramblings help at all.
-Rick

[Brad97GS]

So it stalls when you hit 40 mph, or it stalls when you slow down after going 40 mph? I'm a bit confused. :)

If it stalls when you slow down after going 40 mph, and it's an auto tranny, my guess would be the TCC solenoid is bad. It's easy to check - you just have to unplug it! The plug is on the front side of the tranny and probably has two wires on it. If the car no longer stalls after unplugging that, then you know the solenoid is bad (and you can drive with it unhooked w/no problem).

If it stalls when you reach 40 mph, then it's something else I'm sure. But I don't know what...fuel pump would be a good place to start I guess. :) Or maybe the fuel pressure regulator, or maybe even a vacuum leak, as they can cause strange things to happen.

[Matt95GT]

I agree with Brad, try unplugging your TCC.

[rixGAphx]

Originally posted by Matt95GT
I agree with Brad, try unplugging your TCC.
I agree also, after puzzling overnight about this.
Assuming you have an auto.

-Rick