nkctb7

Finally my CEL came on as I was experiencing misfiring. Code P0161 showed up on a scan. I know that it refers to the left side post cat 02 sensor but I want to make certain that this will cure the misfiring issue that I'm experiencing. Any help is greatly appreciated.

Cheers

Ausmbtech

That wont have any effect on engine running in ANY way.
The downstream o2 sensor is there solely to monitor cat function. If it doesn't bring an engine light on and you don't have emissions testing for rego then don't worry about it.

With your scanner can you look at engine adaptation values or smooth engine running?

benzslo

Agreed. Replacing that o2 sensor won't cure your misfire.

nkctb7

Thanks guys! I was encountering misfiring on cylinders 5,6 & 7 prior to replacing valve cover gaskets and breather seals as oil was seeping into the plug cavities. Although not nearly as bad as it was, it still feels like something is causing hesitation and holding her back at full throttle. The cel finally came back on and those are the codes that popped up during a scan. Perhaps it is a bad plug that is causing the misfire. I cleaned the maf sensor a few months back as a scan recognized a hot film build up in the maf. Perhaps, it is on its way out! Would a faulty maf not show up on a scan? I also cleaned the fuel system, thinking that that an injector was clogged. This is very frustrating, to say the least! Coils are new and wires appear to be good. I'm running NGK iridium ix plugs and perhaps they were not a great choice.

nkctb7

Secondary cats have been removed. I suppose it is cylinder #3 that triggered the cel to come on. I will check to see if the scanner shows engine adaptation values.

Cheers

ECTurboGSX

When my MAF died, I could feel the drop in performance long before it threw a code. Unfortunately, it is tough to tell if that is the cause until it does throw a code unless you don't mind throwing parts at it. There may be a diagnostic that can be done on the sensor that I'm not aware of.

nkctb7

Thanks for the info.! I'm hoping that the maf is the culprit. I read that cleaning the maf is only a temporary fix. Would a bad maf cause misfiring on various cylinders? $150 is a small price to pay if it cures the issue. Do you recall what the scan read when it eventually detected your faulty maf?

Cheers

benzslo

Often times a bad maf will show up in misfires before it shows up setting faults for the fuel mixture adaptation. They will run so badly in the upper rpm range that it will then misfire.

cm60k

+1,

MAF is an Enemy to all air system, either ECU doesn't like it..,

the MAF film is soo sensitive and not gives clear codes while the car is running...

ZAYED,,

benzslo

it may not give off a code, but it is still easily diagnosed if you have the test equipment to look at the part load fuel mixture adaptations... they will be getting towards 1.30 both banks.

cm60k

Good idea, Thankss

ZAYED,,

ECTurboGSX

I don't remember the exact code, but I think it will give you two codes which will be something to the effect of Lean Fuel Mixture Bank 1 and Lean Fuel Mixture Bank 2. When you see the same code for both banks, that is what indicated the MAF failure on mine.

nkctb7

Problem eliminated! Added 1 bottle of Chevron Techron fuel system cleaner to the gas tank when almost empty. Added no more than 15 gallons of fuel and after a few days it started to run better. Added a second bottle when fuel was low and a few days later the cel went out and runs like a charm now with no hesitation or misfiring. It has been three weeks now and still running strong. Thanks to everyone for their input, help and advice.

Cheers

DRBC43AMG

Good job and also a sign that perhaps the injection system needed come cleaning. Something which could be done from time to time (1-2x a year)