Need help on deceleration pop
 

I have a 2010 2ss ls3 (manual) only mods are cai and kooks Lt headers and straight piped. My decel used to be loud and constant. Now it's just random I don't get it all the time like before if feel something is wrong,and when I get no decel pop and come to a complete stop my rpms stay revved high around 1500-2000 for about 4 seconds then it drops back to normal idle. Really weird. Thought it was a vacuum leak but was told if I had a vacuum leak rpms wouldn't drop to normal they'd stay up. Need help guys any ideas on what it might be?

Decel IS random.
Has it been tuned?

Not sure if the hesitant idle drop is related to the lack of normal decel pop, but it's certainly not normal. Gotta ask the same thing as Orange, did you get a tune after the mods, specifically if you deleted the rear cats and O2 sensors? My decel popping became a bit more pronounced after adding LTH/HFC's and a tune.

I think I read on here that decel popping can actually be tuned out? :iono: Either way, sounds like a job for your tuner to take a look at. If it isn't tuned, start there.

start at the front...clean air filter?.....strong maf?....good plugs?...plug wires?...any vacuum leaks?(check all hoses any way!)

and then is it tuned? with your mods would be a good idea...keep the exhaust valves from burning out(car is running lean..guaranteed)..

btw - put your mods in your sig...saves time!

Car has been tuned a day after mods and I might want to check my air filter which is probably the only thing I have not done. I've checked all hoses and plugs were just changed out.

the tuner might have tuned the deceleration cut off off

In my experience decel popping usually means you need to add more fuel to you map just before the pop.

If it ran perfectly after being tuned, something has changed. An unstable idle is often on the intake side.

I'd take a close look at the the entire CAI and PCV. Is the air filter old...replace. Pull out the MAF, disconnect. Get a close look inside the MAF with a light, make sure the hot wire sensor is not all fuzzed up. Reinstall, reconnect MAF.

I'd take the CAI pipes off, reinstall - retighten. Just to make sure no leaks on the intake side. When off, you can also peek at the throttle blade, throttle body and make sure it is not uber carbon'd up. A lot of carbon around the throttle blade can cause an unstable idle.

A good clue on the PCV side is.... get the engine fully warmed up and idling. Pop the oil cap off quick. There should be a brief little stumble/change and then resettling of the idle. If you can pop the oil cap off without any noticeable little change in the idle... the PCV system is not sealed.

An over-oiled air cleaner can cause these probs. Mucks up the MAF.

I'd start with all those CAI, MAF, and PCV checks. Keep in mind tuning doesn't change.... If it ran perfectly after initially tuned.... and now doesn't, something has gone wrong.

Decel fueling, popping or no popping can be adjusted in the tune. After LTs and CAI, mine was tuned for no popping and it never has. Just a slight burble on decel. Not a single backfire since I loaded a tune from Ted at JRE. Which is exactly what I wanted. To me... backfiring sounds like a clunker that the muffler fell off.

What tuner do you have?

From what I gathered the decel pop is actually from the fuel being cutoff. It can be tuned out. Having it or not wont hurt anything. Ask a tuner.

I got it tuned at izzy's performance. Real cool guy that knows his stuff

Yea even after the tune I had alot of decel pop, which I love honestly, but maybe after a year now that it's been tuned I started noticing that it doesn't pop as much as before and my rpms stay stuck high sometimes, but thanks alot guys you guys really are a big help and I appreciate it all the tips you guys have for me. I will check into my intake it's the only thing I have not checked I'm sure the filter might need replacing since I havent cleaned it since I installed it which has been a pretty long time. I had checked the throttle body already and cleaned it all up as well as the maf sensor.

Decel pop is all related to what is called "deceleration fuel cut off" or "DFCO". When the car is on deceleration, the fuel gets cut off and then you get the popping. You can tune for more pop...or no pop at all.

The other thing that can affect how much pop you get, even if you are trying for it, is exhaust leaks. Sometimes headers leak where they connect to cats or o/r pipe and this can decrease the pop.