snichols96

Hey there mine was doing the same thing as far as the poping and bogging I wound up installing new plugs, wires and both coil packs, now she runs great

AirBrontosaurus

How fast do your RPMs drop? Do they plummet super fast, or slowly crawl down to idle? Does the popping go away when you're at idle, or is it pretty much constant? Do you have a wideband, datalogger, or some way to see what your fuel trims are doing? What kind of things does your chip change?

It sounds like you might have a fueling and/or dashpot issue. The popping sound could be normal, as when your car shuts off the injectors on decel you have engine braking and you're detonating/burning small quantities of gas in your exhaust stream. The shutting off could come from the IAC (they break like it's their job. Just cleaning it isn't always enough, often you just have to buy a new one), or fuel flow problems, or a squiffy dashpot setting (the dashpot controls how fast your engine falls to idle, among other things).

My car used to get really close to dying on decel, as well as having my RPMs drop far too quickly. My fix was to increase the minimum timing at low RPMs by about 10*, which cured the problem entirely. Granted, my problem isn't identical to yours, and the timing won't have anything to do with the popping, but it may fix the dying.

If you can do some datalogging that would be supremely helpful. Otherwise I'm just firing shots in the dark. Good luck!

AirBrontosaurus

Yep, it could also be something as simple as the plugs. That's an easy/quick fix, so maybe start with that. Although you would think that bad plugs/CPs would throw some sort of CEL...

Lowtryx

I think you are on to something with the timing. But, for now a quick way to tell exactly what's been going on inside your combustion chamber is to pull a few plugs and look for any tell tale signs. Other than that, is there any. Chance of reverting to the stock tune? Could also be part of the issue. Look into the ignition (spark, timing, cops).

AirBrontosaurus

The problem with pulling the plugs and looking at them is that with this kind of problem they most likely won't tell you anything. Unless your car is majorly messed up (in which case it would be throwing codes galore), your mixture is always going to be about right at part throttle, and your idle is always going to be on the lean side. The ECU makes sure of this, and does a very good job of it. It does this by design, and if for any reason it can't keep the ratio it wants it will throw codes.

This means that in order to read the plugs in this case, you'd pretty much need to drive until you had the problem, kill the ignition immediately, and then pull the plugs. If you let the idle stabilize, even for a second, then the plugs will be "purged" of the previous mixture and will only show the normal, whitish-gray dusty look.

If you have had a problem constantly for a long time, you may see it in the plugs, but since this is a new issue, and it is only present for small spurts while driving, the mixture is (assumedly) correct 98% of the time. That 2% is what we want to find out, but it wouldn't show up on the plugs, or if it did it would be covered up by the other 98% when the engine is running fine.

The plugs may tell you if one is fouled, but I would be surprised if you could tell any important mixture information from them. Still, checking the plugs for things like carbon deposits or broken electrodes couldn't hurt. Hopefully the fix is something quick and easy like that.

hiboostwoody

Might check your mass airflow sensor also. Could need a good cleaning or replacement.

uberstang1

Well if you have suspision that it has something to do with the superchips tune the first step would be to return to stock programing and see how it runs, how many miles have u ran with the superchip? I know a few people that went with superchips and had nothing but problems. But like everyone else said some of the usually suspects could be coil packs/wires/plugs/ fuel delivery issue/ MAF/ IAC/ TPS

snichols96

That is what i was thinking too about the cel, however mine didnt through any and it was idleing like it had a big cam and all once it got warm. I had one coil that the houseing was brock at the harness plug in. A simple tune up can cost around 250, you could also use a timing light and see if you are bouncing around at the timing mark

disposablehero27

Thanks for all the info guys, i have an IAC on order, be here tomorrow, guy at the autopart store says thats prolly the issue, to smack if with a driver/wrench a few times, see if that helps it temporarily. Tried that, seemed to cure it, but that idle does whatever it wants, when i slow down, it drops a little faster than normal, however it doesn't stop at like 900/1000 it goes to zero. the tuner is pretty much useless at this point, gives me err8, whatever the hell that is, so gotta call superchips and figure out who knows what they are doing so i can talk to them. I don't have any datalogging/wideband.. nothing really but tools and signiture modifications. As far as the popping and cracking in the exhaust, it only does it when reving down, it always used to if you hit anything about 3200 or so and let it rev down, now it seems ALOT more frequent with normal driving, it doesn't do it at idle at all, but its a rough idle for stock internals, its like it has a small cam in it, the car shakes and vibrates lightly, you can lightly feel it.

masterofthepuppets99

my stang has no mufflers or cats and it crackles and pops on deceleration all the time starting at 2000rpm's so im not sure if you should be concerned about that