Where is the throttle positioning sensor of my 2005 Chevy Coblat LS. If this a do it yourself job or 500.00 at the mechanic?
Country: United StatesMake: ChevroletModel: Cobalt LSYear: 2005Engine: 2.2 L
Changed spark plugs, wires, boots, fuel and air filters. Cleaned out the fuel injection system. Car still idle rough and sometimes will stall after coming to a stop.
Do you have a check engine light on and is the engine missing?
Yes, the engine light is on steady. No, it does not seem to be missing. It just idles rough when I come to a stop, and sometimes will stall. It starts right up again though. The code that came up was P0178, if that helps any?
Hello , my name isXXXXX you for choosing justanswer.com.Are you sure about the code PO178 as that is not a code in any of my databases?
No, I am not sure, I have it written down at home and I am out of town until tonite. Are you Jay?
No, I am a new expert. I can help you if you supply the correct code here. I will keep your question open. You can get back to me anytime answering any e-mail sent to you related to this question or by logging into your JA account. Thanks again, JHoop
Will do. Thanks.
Great. Have a nice day, JHoop
Hello,Customer this is Jay, JHoop is correct in that code P0178 does not exist, therefore you may have made a mistake in writing the code down or in your memory. Please check again and repost. In just what you are mentioning it may be a catalytic converter issue, but I don't want to jump to any conclusions. Let's wait till we have the correct code. Thanks.
The codes are P0171 and P0128
O.k. That helps more! P0128 is likely being caused by a faulty thermostat, so your best bet would be to change the thermostat. P0171 is a lean condition get an appropriate cleaner such as brake clean and spray out the MAF sensor. Also make sure there are no intake leaks such as the air intake not hooked up properly. Do you use an oiled air filter? Please reply if this does not help, thanks! Feel free to reply to the air filter question.
5 yrs experience, GM Trained,
What is the MAF sensor and where is it located? I just recently changed the air filter and had a hell of a time replacing the cover. The light came on a couple of days after that, so maybe I didn't seat the cover properly. I don't use an oiled filter. I just put it in right out of the box. The problem with the rough idle and stalling started a few weeks before and the engine light had not come on. My original question was about the throttle positioning sensor? Would a faulty one cause the rough idle and stalling problem?
I don't think your throttle position sensor is the problem because you would likely have other issues and codes. The MAF sensor is located just past the air filter in the air intake stream so my guess is that you didn't seal the air filter box. Once you have replaced the thermostat and sealed the air box please report and let me know how it is running.
Is it attached to the wiring harness just past the air cleaner? Should I clean or replace the sensor as well?
Yes it is just past the air cleaner. It measures air flow and is inline with air intake.
Thanks. I'll try it.
Remember, please reply after you have done these things and let me know how it is working. If it has not fixed it then we'll continue to figure it out.
Hi Jay,I cleaned the sensor, checked the air cleaner cover and it seems to have improved the idle. I don't think the thermostat is malfunctioning though since my heat works well. I reset the engine light and it stayed off for 2 weeks. When it came back on, the only code was P0128. Anti-freeze level is fine. I may try changing the ECT sensor when I get a chance.
O.k., although I'll let you know that in my experience a P0128 code usually is related to a thermostat that is not working correctly. Thanks.
Is the thermostat something that I could replace on my own or should I leave it to the pro's?
Thermostat on these is a touch difficult and perhaps would be best to take it into a shop to get it done, Please reply if you have any questions, thanks.
Just letting you know, I had the thermostat and sensor replaced and the problem is solved.