Hello all. I searched and couldn't find anyone with my exact symptoms. So I decided to ask.

I just got a 1995 Avenger ES 2.5 Auto tranny for cheap. I have a few issues(among several - did I mention cheap??) that I cannot seem to figure out.

Issue one. I start the car it idles semi-rough. Sometimes it dies, kind of gradually. I can usually get it to hold a sorta weak sounding idle. Kind of rough but not sure I can say it misses.

Then I put it in reverse and before I get to the foot of driveway, it dies. Then it dies basically dies every time I let my foot off the gas. I CAN keep it running by holding and tapping gas pedal, like you would in an old car with the idle set too low. The car ALWAYS starts right back up. For the most part it is drivable. Tonight it did a shut down, pause, then start right back up thing. It didn't have alot of low speed power. After I got home, I was idling it in the driveway and it did a click-shutdown thing. Similiar to the off-back-on thing while driving earlier but without the momentum, couldn't restart. Started right back up with the key though and idled 'weakly'. Sometimes the I notice a rotten egg smell from the converter and other times a strong smell of not being started for a while.

Basiaclly wont idle while driving and below 2000 RPMS its erratic at times.

Intake air temperature sensor replaced. (had code for this)
TPS has been replaced. (stab in the dark)
Idle air control valve has been replaced. (stab in the dark)



Issue two. In order to pull codes in an attempt to diagnose, I found Autozone is not able to do a '95 avenger with their machine. Apparently the Avenger is a kind of OBD 1.5 thing and you need an adapter. I have been able to pull codes. The are listed below.

Code 12 - Battery disconnected within last 50 key-on cycles. Due to battery being removed recently

Code 23 - Intake air temperature sensor voltage out of range. This has been replaced.

Code 71 PCM output voltage low. Haven't resolved. Not sure what this means exactly.

ONE TIME I got Code 21 - O2 Sensor circuit problem, sensor voltage to computer not fluctuating. This show up suring one 'key-dance' session two days ago. Hasn't shown since.

Issue three: Sometimes when I attempt the 'key-dance"(on-off-on-off-on-count-the-blinking-light) I get nothing. After the key strokes, CEL goes off and never blinks. Example scenario. Tried key-dance at Autozone. Couldn't get flashes. Went down street a block and washed car. Pulled up next to the vacuum cleaners when done and tried the key-dance and it pulled 12-71-23-55. In that order. Got home and key-dance wouldn't work.

I did unhook the battery yesterday but for only 5 minutes. Not sure if that was enough time to erase codes. (may explain the removal of code 21)

After I reconnected the battery, couldn't get the key-dance to work. Hadn't worked since until immediately after the car wash. Then basically hasn't worked since.

One thing to note is that all this time, the anti-lock brake light is also on. I am slowly going through that sytem as well.

Any thoughts on the idle problem and intermittent key-dance failure. I am thinking it may be related.

Thanks in advanced

 

Just did the seafoam treatment. The car is beginning to run great. Just won't idle.

 

as for the idle the car is fuel injected you should never have to press the gas to keep it idling/running
1st clean the intake tract with seafoam or intake cleaner
Cleaning the TB and intake tract usually clears most troubles

2nd Block off the EGR and see if the idle improves
Bad EGR can allow unmetered air in causing bad idle
A simple gasket made out of a pop can works well
If the idle improves either leave it blocked off or replace

3rd remove the IAC and clean it with intake cleaner
Sometimes cleaning will fee it up and return operation
LAST replace the IAC

 

Thanks Bad Venge. The IAC has been replaced. The EGR and all attached vacuum lines 'APPEAR' new. And I did run seafoam through it. Now it idles when just sitting in the driveway. Once I put it in gear, it dies almost every time I let off the gas.

I adjusted the throttle cable bracket back which helps. I know thats not the proper method and is only temporary.

I left the battery unhooked all afternoon while changing the plugs and wires. Doing the key method to get the codes is still returning the following.

12 - battery unhooked
71 - PCM output voltage low.
23 - Intake air temperature sensor voltage out of range.

The intake air temperature sensor has been replaced.

Could my PCM be shot? I still am only having sporadic success getting the PCM to give me codes. Using the key method(0n-off-on-off-on-count the blinks) method.

 

BLOCK off the IAC first it's 90% of the idle troubles
The more parts you blindly throw at it the more chances that you induced other troubles

 

Block the IAC? Do you mean EGR?

 

sorry yes

 

Okay, so here is where I am at.

I currently have the EGR valve blocked. seemed to help, but still dies at stops about 60 percent of the time. Also a couple of times while driving, the engine will just shut off and both the check engine light and anti-lock brake light will go OFF. Then after a couple of seconds, both lights come back on and the engine kick back up. The couple of times it just shut off in the drive way, it always fires back up.

Recapping, here are the codes I get, WHEN IT WORKS

12 - battery has been unhooked to try and clear codes
21 - Oxygen sensor (this started after I blocked off the EGR)
23 - Air intake temperature sensor
71 - PCM output voltage low
55 - End of Codes

Here is everything I have done

replaced air intake temperature sensor (error code 23)
replaced I.A.C. valve
replaced TPS
ran seafoam through system a couple times.
replaced plugs and wires
currently have EGR blocked off

 

check for vacumn leaks around the manifold /TB listen for whistles ect spray TB cleaner on suspected leaks if te idle revs /stalls or smooths out

 

Will do. I did it to a degree, but I am sure I could have been more thorough. Is it possible my computer is caput? I say that due to the internittant nature of my ability to retrieve codes and error 71.

Thanks for all the advice BV. Also, thanks for your permission to use your car on my site. I am holding out for some good nose shots of your car. No hurry.