pops out exhaust on decel...

[IndyBlk5.0]

Seems like it is poping out the exhaust on deceleration. and when i give it just enough gas to keep a steady speed it pushes and pulls. I'm not sure if it is a misfire or not. timing is 13*, fp is at 38 vac on. tps is at .98 and idle wants to jump around a bit. Any ideas?
Also, I hear a hissing sound around the upper intake. I sprayed everything i could with carb spray and heard no variations in idle speed. It sounds like a vacume leak. It could be the throttle body but it sounds more down by the runners.

 

[IndyBlk5.0]

anyone?

 

[Scott_B]

Pretty much any 5.0 with aftermarket mufflers i've heard pops when you let off the gas and let the revs fall by them selves. This is of course while driving under load.

As for the hiss..sounds like a vacume leak..not sure what else to tell ya on that..

 

[proxses]

Did you spray around the fuel injectors? Sometimes the o-rings get old and the manifold can leak there.

 

[5.0guy]

not having cats will do it

 

[IndyBlk5.0]

The injector thing might be my problem. That makes sense... Well before the car never popped out the exhaust when i let my foot off of it and let it decel on its own power. But, I did change from a h to a x pipe

 

[TheDamned]

The injector thing might be my problem. That makes sense... Well before the car never popped out the exhaust when i let my foot off of it and let it decel on its own power. But, I did change from a h to a x pipe

my 5.0 pops since day 1 i purchased it... I bough an mac o\r h-pipe and the pop is awesome

 

[Ray@VSK]

Cackling is what they call it, I do beleive. it's normal, I would not be alarmed, I like it actually

 

[5.0guy]

yeah, sounds cool when u decel by downshifting..

 

[IndyBlk5.0]

sounds like i have hillbilly cherry bombs on it

 

[5.0guy]

sound clip?

 

[Mike86Stang]

It's lean backfiring on decel because it so lean (high vac/ injector pulse width goes way down) ... fatten it up just enough so it stops & you should be good. been there many time before bro.

 

[IndyBlk5.0]

it eats enough gas the way it is!!!

 

[PNY PWR]

I get some cracklin too w/ off road H and dumped 40 series Flows

 

[IndyBlk5.0]

I turned up the fuel pressure. Still same problem... Feels like im getting a slight miss at part throttle holding the rpms at low load.

 

[L8 MUSL]

I turned up the fuel pressure. Still same problem... Feels like im getting a slight miss at part throttle holding the rpms at low load.

Have you changed your plug wires lately? That is exactly what that part throttle miss sounds like to me.

 

[IndyBlk5.0]

Have you changed your plug wires lately? That is exactly what that part throttle miss sounds like to me.

No I havent.

 

[IndyBlk5.0]

I found that one of my plugs was allitle loose, so I tightened that up. No change. So I just purchased a 75mm Pro M billet calibrated for my 24#'s to see if this will help. It's going to be installed soon. It feels like a skip, but I can hear the exhaust sound like it's misfiring (surprisingly like the poping noise on decel) when I barely give it any gas. Any other possibilities?

 

[NYC LSC]

I had the same damn thing happen to me recently. Same MAF sensor, too.

Replaced it with a 76mm C&L and the car has no more jerking, no more popping out of the exhaust (there's a little, but it's not as bad as before) and the car idles like a champ.

So in short, mine was a bad MAF.

 

[IndyBlk5.0]

I have a 73mm C&L right now, I've heard horror stories, so I decided to change it. I am also going to get some Accel plug wires, if I can't find any FRPP wires soon.