cknoma2005

iTrader: (3)

My car will idle really low at times and sometime die when taking off in first gear well after it has warmed up. The car has a cam\tune and many other mods (listed in sig), It seems this may have started happening after I switched my pcv valve over from the old ball valve to the newer (ball less) orifice hole style. I know that sounds funny. I also changed from a flowmaster catback to a custom bullet style exhaust which is actually more free flowing. Now the car was tuned with an open cutout in the I-pipe. The cutout is no longer longer on the car. I don't think that is the issue because it would idle fine with the cutout closed flowing through the flowmaster catback.

Could it be the pcv change, o2 sensors(never been changed), exhaust, tune?
The car is throwing no codes and I had it scanned at Oreilly.

Any ideas would be helpful. Thanks.

blade2222

Try cleaning the throttle body first. Fixed a idle problem I was dealing with.

cknoma2005

iTrader: (3)

anyone??

cknoma2005

iTrader: (3)

throttle body blade appeared to be clean when I looked at it last, but I will check again.

cknoma2005

iTrader: (3)

If there is something wrong with my o2 sensors should they throw a code?
They appear to be the OEM style with vent(slots) on the end. I never replaced them. If they are the original o2 sensors and after 158,000 miles, one would think they wouldn't last that long. I don't have rear o2 sensors since I do not have cats. The rears were turned off when I had the car tuned.

blade2222

I'm surprised they have lasted that long, I would replace them just because there so old. They can't be operating very well. You'll probably notice a difference as well as some added fuel economy.

cknoma2005

iTrader: (3)

That is a good point, but I should note that I bought the car with 116,000 miles on the clock. I guess its possible they could have been replaced before I bought the car.

What is the average lifespan of o2 sensors? Which ones are good to buy besides oem?
NGK, Denso, Delphi, AC Delco?

edcmat-l1

iTrader: (10)

Depending on the PCV setup, it can pull a significant amount of idle air through it. So yes, just changing the PCV can cause idle issues.

If you don't have any scanning/tuning software, you can try cracking the throttle blade, and then doing a TPS reset. Crack the blade a 1/4 turn on the screw, then unplug the TPS, and turn the key on. Wait 30 seconds. Turn the car off and plug the TPS back in. Test drive. If it's no better, crack the throttle blade another 1/4 turn on the screw, and repeat the TPS reset procedure. Basically what you're doing is getting the idle airflow back where it was with the original, higher flowing PCV valve.

cknoma2005

iTrader: (3)

Okay I will try that.

Its just weird. It idle fine most of the time, but sometimes when I let my foot off the throttle it will drop below 800rpms (normal idle) to like 400rpms or so. Then I have to rev it back up in order to correct it and keep if from dying. It does this the most at slow stop and go speeds like in parking lots or traffic.