A week ago, the battery was near nothing in my 1998 Camaro Z28 LS1 auto with 253,xxx miles and wouldn't start. I can't complain, the battery was 6 years old. I charged it before I replaced it, and the car ran terrible. High idle, surging, and so on, along it very unpredictable starting (sometimes very slow cranking, other times more normal). So I replaced the battery on Thursday instead of fooling with it and worrying if it would quit.

Put a few hundred miles on it, everything was normal, and on Monday out to lunch, the Service Engine Soon light came on. Yesterday, I was able to get the codes checked at AutoZone and Advance Auto. The codes were:


• P0137 02 Sensor Circuit Low Voltage (Bank I Sensor 2)
• P0171 System too Lean (Bank 1)
• P0174 System too Lean (Bank 2)
• P0507 Idle Control System RPM Higher Than Expected


Information I have found or have been told is:

- Fuel Injection Idle Air Control Valve needs replaced
- Left and Right Bank O2 sensors need replaced
- MAF may need to be replaced
- Injectors may be dirty
- May have a bad injector
- Vacuum leak in intake
- Use CRC Mass Air flow cleaner
- Use Seafoam cleaner

Basic look over of the engine, I can find no hoses loose or leaking. No connectors loose or wires broken or worn. Plug wires are only 25,000 miles and are on and secure.

So what does the forum recommend?

 

With everything showing lean, I would start by checking the fuel pressure, before going for the gusto and replacing a bunch of parts that may be in good working order.

 

It sounds like you have an air leak somewhere. The IAC valve is probably shut down as far as it goes, hence the idle code. Check the rubber elbow at the rear of the intake manifold on the driver side. Those get holed very frequently. That elbow goes to the pcv valve on the passenger side. The PCV valve could be stuck open but are cheap to replace. However, it is buried in layers of tape and tubing midway toward the back of the engine. Also check the hose from the pcv valve to the throttle body.

 

the obvious question is

do not look at the warning light

how does it run?

if you say it runs ok, but you have those lights, then if you don't have the scanner which can clear codes, then unplug the battery for 15 minutes

then, run it and see if you get the light again

if so, then check for the codes and see if any have disappeared.

As Pete said, lean means a lack of fuel. A fuel pressure check at the rails would either eliminate that or confirm fuel press. as the culprit but, how is it running right now?

 

Thanks everyone.

Based on a combination of replies everywhere, I figured the best and cheapest place to start was a good cleaning. I got a can of Sea Foam and a can of CRC MAF cleaner, filled the tank and dumped the Sea Foam in. Drove 60 miles home Thursday night.

I then sprayed the MAF and IAC with the CRC cleaner and let it sit overnight. Drove 60 miles to work and 60 back, the Service Engine Soon light was still on. I went to pick up a friend for dinner and the SES light went out, after about 170 miles from the Sea Foam.

It hasn't come back.


When the SES goes out, have the codes cleared, or does the light just eventually time out? Do I need to get the codes read again, or will they be gone?

The car only did a bit of stumbling after cleaning the MAF and IAC but that stopped after about a half mile.

The idle is a bit up on cold start now, but that goes away after about a half mile, too.

 

Many codes do not yet clear once the SES lamp is out. That depends on the code. Some take 3 ignition cycles to clear the code, others take many more.