I have been getting a P0131 for years now-many of us old timers have gotten it after changing air intake, along with the T/C light coming on. I got a P0171 twice, posted my problem. I removed the injectors and cleaned the bottom part (I have not taken them off the fuel rail yet), cleaned the MAF, and changed the air filter. For about 30 minutes I was code free, then they all began coming back on. I was advised to change the O2 sensor, and again for 30 minutes drove code free before they all came back. The problem now is that I am getting the P0171 frequently now, along with the standard P0131 code.

My impulse would be to get new injectors-they have 85,000 miles on them plus lots of extra hours from heavy-traffic driving in NYC.

Any thoughts on this? My inspection expires in 10 days. Thanks for any help you can give me.

Also, Don, I know you are very knowledgeable about our cars. I have 2 codes-PO301, cyllinder 1 misfire. I switched coil packs and put in 4 new plugs. Still code. Think it could be the injectors need to be replaced? Also, just got this new code tonight-PO171Generic misfire system too lean bank 1. What does this one mean?

Just did an internet search and thinking they could both be from a bad injector. They look easy enough to change-just remove fuel rail and they pop out.

For that P0171. Clean the MAF sensor first

https://www.obd-codes.com/p0171

"just" pop out is not exactly my experience. It takes some work and a new seal set.

I would do a compression check first before spending money on parts.

Will do, but no reason to think there are any problems. Car is running great except the idle has been rough and gas mileage has dropped lower than usual (for mostly city driving).And have had the number 1 cylinder misfire for a while-this could easily explain the po171 code also.

that P0171 usually is intake system related including vacuum leaks; a misfire usually give a specific code for that cylinder. Triggered by 1st downstream O2 sensor.

If you let it go it will turn into a bad catalytic converter.

If y'all read the link I posted, it could be a cracked flex pipe !
But first try the MAF cleaning!

Well, I have been checking for the past 4 days and have not gotten that PO171 code again. Only happened once. Now just getting the same PO301 code which I have gotten for a long time. I just put in a bottle of Techron fuel injection cleaner-maybe a miracle?

The issue which keeps giving me codes-TC and check engine- is that age-old problem so many of us have had. Back when the car was new, I began modifying it. I did each thing one at a time to check on performance and see the difference each made. First the exhaust-different muffler and added a y-pipe for dual exhaust. Then had the computer reprogrammed. Finally, added a CGS cold air package. A few days after that, I got hit by a speeding car directly in the right rear tire. Shortly after getting the car back from the body shop, I began getting the TC code (I don't think it happened before the accident.) At first, I only threw the code if the wheels spun, like from a burnout or wet leaves. After restarting the car a few times, the light would go out. But it got progressively worse. Next, it would code anytime I accelerated hard. Sometimes after hitting a bump or pothole. Next, just driving around then the light would come on. Finally, it happens randomly. I could be totally stopped at a traffic light or waiting for somebody, and the light will come on for no apparent reason.

In the beginning, this was a big topic on the forums. We thought it only happened to people who changed their air cleaners. At first, oil from the filter getting on the MAP or MAF sensor was thought to be the cause. I cleaned both, then replaced both. Next, it began happening to people with stock HHR's, with the factory air cleaner.

This remains a mystery to me. When the code throws, the car goes into limp mode, with the hard shifting. Then after a while, the light goes off by itself (or if I reset it) and the car is fine for a short while until it happens again.

Hmmm... I wonder if something was damaged in that accident? Wheel speed sensor, wiring? just enough to give you an intermittent problem.

https://www.chevyhhr.net/forums/prob...92/#post723591

That was my first thought-but keep in mind that many, many other people have the same TC code problem that have not had accidents. And remember that I do not have to be moving for the light to come on. Sometimes I start my car in the morning, let it idle for a few moments, and the light will suddenly come on.