Our Community is 940,000 Strong. Join Us.


3.1 v-6 idles and shifts rough, codes 23 and 44


a_kraker99
06-02-2005, 03:03 PM
I have a 91 corsica 3.1 L V-6. The car idles pretty rough and when I am driving and I let off the gas going about 50 in 4th gear the car shakes as it downshifts to 3rd. (I used to not get 4th gear, but i replaced the TCC solenoid and now it works). The problems seem to get worse when I use air conditioning, maybe because the engine is just getting hotter. I got the codes from the check engine light and I got codes 23 and 44, which are "MAT sensor low temp indicated" and "oxygen sensor lean exhaust". i thought maybe the o2 sensor was bad so i unplugged it to see how it would run, but it didnt change except that i got the code 13 now too.

jsgold
06-02-2005, 10:59 PM
Code 44 has several possibilities according to my 91 GM service manual. The code will set if, IAC circuit shorted or valve itself bad, O2 sensor wire shorted (maybe against motor exhaust), contaminated fuel, low fuel pressure, bad exhaust leaks, lean injectors, or even the O2 sensor itself. Might want to clean the IAC and all around it, spray injector cleaner into the intake area while running, check the intake (rubber) assy for cracks/splits, change the fuel filter, and check all wiring to O2 sensor and to the IAT sensor. Run some injector cleaner through the tank too. Check for vaccuum leaks also, especially to the MAP sensor. Doubt the exhaust is the culprit, but check it too. Our 91 had some issues a couple of years ago with poor idle etc., and the intake hose was shot, and the intake / IAC etc. needed a cleaning and general engine tune up, along with two vaccum lines replaced. The ECM's do go bad due to water leaks, and will set "false codes", but since yours is running rough I doubt this is so. If you are getting a bad vibration from engine, I wonder if you might not have a bad coil pack or broken wire. Our 91 was bought new and we have replaced a lot of parts over the years. Been a good car though, generally not too tough to work on. Tune it up, replace old vaccuum lines, clean the intake, and see what happens. Be sure to reset the idle after cleaning the IAC. Since you have to unhook the battery when replacing or removing ANY sensor it will be best to start the engine, don't give it any gas, and let it idle for 10 minutes on it's own before driving or giving gas. Advise anything found so you can get help from the folks here on this problem.

a_kraker99
06-03-2005, 11:40 PM
i just replaced the o2 sensor and it got rid of the code 44. it seems like it runs better and doesent shake anymore when i let off the gas but it still idles rough and has a code 23. that code has to do with the MAT sensor sensing too low of a temp. I tested that sensor and it looks bad too. do you think the mat has something to do with how the car idles?

jsgold
06-05-2005, 09:53 AM
I suppose it is possible, but, I have never had one of these sensors go bad on any vehicle I have ever owned (mostly GM). Hopefully others here can answer that but I still think the IAC needs cleaned /replaced, or, if the idle has a steady "miss" to it, there could be a bad coil pack. You have three of them and one failing will cause a very poor idle, vibration, and poor running conditions that can trigger codes. Need to test the firing on the engine to see if proper fire exists.

cstar
07-13-2005, 01:39 PM
My sister just bought a 90 corsica it ran very rough someone told her that she needed to replace the one of the igniation coils. It costs about 20 dollars at auto zone.

Add your comment to this topic!