3.1 Wants to Stall During Warmup

[3X00-Modified]

Ok, something that didn't get covered...

Have you replaced your Crank sensor in the back of the block? Sometimes when those go bad they will throw off the timing when they warm up and cause the motor to run like crap, or not restart when warm.

[john266]

Yea, believe it or not, when I paid a local mechanic to change the oil pressure sensor for me last year, he mistook the CPS for the oil pressure sensor and broke it. Hence, I got a free new CPS installed. So yes, it has been changed.

[3X00-Modified]

Well next few items to check would be the ICM if that hasn't been tested or coils. I know on the older 3.1's they were kept up under the front exhaust manifold and the heat would cause them to degrade quickly.

[Money pit Beretta]

The ICM has been changed. John, I can see why this is driving you crazy. I'm running out of ideas. I have never had a coil make that kind of problem.

[john266]

Hehe....I'm just as puzzled as you guys. I consider myself fairly automotive competent (work at Advance), but I myself have never seen a car do crap like this before either.

I guess I'm gonna keep messing with the car again first of the week, and I will start by changing the fuel filter again to see what happens.

I really appreciate everyone's help with this!

[john266]

Just posting an update to this thread....
After a month of sitting in the repair shop with no results, my car is once again sitting in the driveway. I think I have managed to find a way to keep the car from acting up on me now. If I let the car idle and warmup 5-10 minutes before driving it, the problem doesn't seem to occur, though the car still runs a little rough (not problematic though). If I start the car up when cold and drive it right away, it always starts falling down on itself about the same distance from my house.

I guess for the time being, I am just going to be driving the car locally and use my truck for all my other trips. I no longer trust my car to go very far in fear that it is going to die somewhere.

[Money pit Beretta]

Cliff? 3X00? Got any ideas?
Hey John, I can send you a vapor canistor so you can make sure that's not it. It is brand new. If it works then we will have to talk about payment, if not just send it back. What do you think?

[john266]

While I do think the problem is somewhat fuel related, I doubt the vapor canister could be the cause of all these problems. I honestly think the problem lies somewhere in the ignition or computer since the problem only occurs during warmup. Since the ignition module and engine computer have each been changed more than once in the last few months, the only thing I could think could be doing this would be the fuel pressure regulator. I am at a loss here...

[Money pit Beretta]

So, does the idle hunt(go up and down)? You did check all your vac lines right?

[john266]

So, does the idle hunt(go up and down)? You did check all your vac lines right?

No, it doesn't. It normally idles fine, even when the car is acting up. It only acts weird when the car is in motion pretty much. You can hold the throttle in a steady position, and once the car starts sputtering you can watch the RPMS just steadily decline until you release your foot off the gas (and it will jump back up to normal). If I feather the gas when the car is doing this (just tapping the gas every second or so while keeping some firm throttle), the car will stay normal, if that makes any sense.

I know it sound weird, god only knows what it could be.

[3X00-Modified]

Lets do a quick recap...

What have you checked/replaced since this started?

Get that list up and I'll try to throw a few more items at it.

[john266]

Lets do a quick recap...

What have you checked/replaced since this started?

Get that list up and I'll try to throw a few more items at it.

List of items replaced in the last few months:
Engine computer (4 times to get one that worked)
Ignition module (2 times just to be safe)
Fuel filter
Map sensor
A few vacuum lines
Tune up (plugs and wires)

The car has had several other items replaced over the last year before the problem started, but that is way too many parts to list. Please let me know what you think.
-Thanks

[Money pit Beretta]

Does the vac line that goes to the FPR have fuel in it?

[3X00-Modified]

You stated before the crank sensor was replaced this true?

Sounds almost like a TPS issue or a coolant temp sensor on the fritz.

[john266]

You stated before the crank sensor was replaced this true?

Sounds almost like a TPS issue or a coolant temp sensor on the fritz.

Oh yes! Thanks for reminding me. I had the car worked on like 6-8 months ago, and the mechanic accidently broke the crank sensor, which was replaced as a result. The problems didn't start until about 2 months ago, so I doubt this would have anything to do with it.

I was considering replacing the TPS just for the heck of it, since it has never been replaced since I have owned the car, and would consider replacing the coolant temp sensor if you think it would be worth it.

Does anyone know as to where the coolant temp sensor is located on the older 3.1 engines?
Thanks
-John