Help with car problems

I have a 96 dodge intrepid thats having some problems.
For the last month or so it's been nearly dying everytime i stop.
Over the last couple of days, it has advanced to actually dying 1 out of 4 stops.
As i'm stopping, once i get to around 8-4 mph the engines rpms go way down - 500 or less. Sometimes it dies, sometimes it doesn't.
I'm not sure what the hell is going on.

Other weird things that probably have something to do with it:
- the car idles REALLy high when in Park or Neutral (around 2200) - when it was new, it idled around 800
- when i start the car, it revs up to over 3000, then sinks to around 2200

More info:
the plugs and wires are new (3 or 4 months old)
the car has 103k miles on it
the transmission is beat up - moving from chicago to los angeles and hauling a U-haul through the mountains can't be a good thing....and then theres the move back to chicago

Please help, what kind of shop do i need to take this to?
will it be worth fixing?

 

[Marshallj]

Originally posted by: jntdesign
I have a 96 dodge intrepid thats having some problems.
For the last month or so it's been nearly dying everytime i stop.
Over the last couple of days, it has advanced to actually dying 1 out of 4 stops.
As i'm stopping, once i get to around 8-4 mph the engines rpms go way down - 500 or less. Sometimes it dies, sometimes it doesn't.
I'm not sure what the hell is going on.

Other weird things that probably have something to do with it:
- the car idles REALLy high when in Park or Neutral (around 2200) - when it was new, it idled around 800
- when i start the car, it revs up to over 3000, then sinks to around 2200

More info:
the plugs and wires are new (3 or 4 months old)
the car has 103k miles on it
the transmission is beat up - moving from chicago to los angeles and hauling a U-haul through the mountains can't be a good thing....and then theres the move back to chicago

Please help, what kind of shop do i need to take this to?
will it be worth fixing?

My Saturn does the same exact thing. I think the coolant temperature sensor is broken, and the ECU never goes into closed loop mode. It's always in a "warm up" mode.

Do you also get crappy gas mileage? Is your car running rich where you can smell it in the exhaust?

 

Gas mileage has always been not so great...I should pay closer attention to that.

I haven't caught a good whiff of the exhaust, but i'll take a huff tomorow and update here.
From what you've said, this sounds like an electronic/computer problem?

 

[Nyical]

My truck did the same thing on me about 4 months back, found out it was the throttle position sensor that died and it was messing with
other sensor.

 

Originally posted by: Nyical
My truck did the same thing on me about 4 months back, found out it was the throttle position sensor that died and it was messing with
other sensor.

What did it cost to fix it?
I've been waiting for some wacko to pull out infront of me so i can just plow into them and collect insurance

 

[Marshallj]

Originally posted by: jntdesign
Gas mileage has always been not so great...I should pay closer attention to that.

I haven't caught a good whiff of the exhaust, but i'll take a huff tomorow and update here.
From what you've said, this sounds like an electronic/computer problem?

Yeah, the ECU controls the engine based on information it gets from its sensors, and when a sensor goes bad, the ECU starts doing flaky stuff. I think one of your sensors went bad.

 

Also, I replaced the ECU last summer. (heh, I...ok, i had it replaced)
I really don't trust the guy who did it either. The problems i was having THAT time was that my fans weren't turning on and the engine and AC were overheating (boilover in radiator, and freeon would all blast out of AC)

 

[Nyical]

75.00 for it, It was for a 99 S-10 and a dealer only part and only took like 10 minutes to replace with old one.

For you car you could probly pick it up at a parts store for alot less or alot more.

 

I payed 575 for an ECU, AC recharge, and a used tire

Will the free autozone scan tell me if it's the ECU?

 

[Marshallj]

Originally posted by: jntdesign
Also, I replaced the ECU last summer. (heh, I...ok, i had it replaced)
I really don't trust the guy who did it either. The problems i was having THAT time was that my fans weren't turning on and the engine and AC were overheating (boilover in radiator, and freeon would all blast out of AC)

It's funny you mention that. The electric cooling fan in my saturn also doesn't come on. It will overheat when I let it run while the car is stopped. I either have to drive the car so air passes through the radiator, or I have to turn my AC on so that the AC condenser fan blows, causing air to flow through the radiator too.

I believe the root cause for all of this (the fan not coming on and the overheating, the high idle, and the rich running condition) is that the coolant temperature sensor is faulty and is telling the ECU that the coolant is always cold. The ECU is probably stuck in the warm up mode, and the electric fan never gets the signal to turn on.

 

[Marshallj]

Originally posted by: jntdesign


Will the free autozone scan tell me if it's the ECU?

It will tell you one of the error codes the the ECU is capable of sending out. On my Saturn, the error code I get is from the O2 sensor. It indicates that my oxygen sensor is reporting an overly rich condition.

The code is kind of cryptic, because the O2 sensor itself may be bad and always indicating a rich mixture, or the O2 sensor may be right and the engine really is running rich.

In my case, I think the O2 sensor is correct, and that my engine really is running rich due to the coolant temperature sensor being bad. This is also the reason why my cooling fan never comes on.

 

I'm going to check and see if my cooling fan comes on
Turning on my AC makes no different (AC doesn't work anymore anyways)

I'll also swing by autozone and have them scan it.

City driving is a real PITA when the car dies at every other stop!!

 

[Pepsi90919]

get your damn ecu scanned

 

[Marshallj]

You can check the ECU codes by yourself, by the way.

You'll have to look it up for your car, but on most cars you put the car in a diagnostic mode and it will flash your check engine light sort of like Morse code- it will have long flashes and short flashes, and you count those flashes and write the code down.

For instance, on my Saturn it will give 5 long flashes followed by 3 short flashes, that would mean Code 53.

Save yourself some money that way.

 

I think autozone does it for free...if not, i'll give that a shot

Btw, the place that worked on it today (tires, tie-rod ends, and alignment) did the engine scan but refused to give me the results.
(i refused to pay 100 bucks JUST for the scan)

My check engine light was off all afternoon, but tonight it came back on - it had to have flashed 50 or 60 times before it stayed lit.

 

[Marshallj]

I dug this up for you in case you want to look at the error codes yourself. I found it on usenet:

you can read out the error codes (if any) in the
computer by cycling the igition switch on-off-on-off-on <then leave it
on> within 5 seconds. Just turn the key to the run position and back off,
don't actually start the engine.

After about 5-10 more seconds, the "check engine" light will begin
flashing out error codes. It does so by blinking out one digit at a time
as in the following example:

flash <short pause>
flash flash <long pause>

flash flash flash flash flash <pause>
flash flash flash flash flash <stop>

This represents a code 12 and a code 55. Code 12 means "power
disconnected within past 15-20 starts", and code 55 means "end of codes."
If the computer thinks all is well, this or just a 55 by itself is all
you'll get.

 

Awesome, thanks!
Where can i find a full list of diagnostics?

 

[Marshallj]

Originally posted by: jntdesign
Awesome, thanks!
Where can i find a full list of diagnostics?

I know the Haynes manuals that they sell at Pep Boys has the error codes listed in it, and you can also find them posted on the internet. I buy the Haynes manual for every car I buy. They prove themselves very valuable.

 

[Marshallj]

Here you go:

Dodge error codes

 

I have the haynes manual, I'll have to look in there for the codes.

THanks alot for the info!

 

[Marshallj]

no problem

 

I was on my way to autozone today when the damn thing overheated

while i was waiting, i did the check engine light thing...the first two codes were 15 and 23...there were two after it, but i can't remember them (i'll check them tomorow - today was hectic)