When I start my 95 in the morning and give it some gas it will pop, also it will pop at high rpms inbetween shifting (m6).

This doesnt happen all the time. but when it does happen its after the car has been sitting atleast overnight or cold

any ideas??

 

First of all where is the popping coming from? Do you have headers? If you do they might be loose because when metal gets hot it expands and when cold shrinks the bolts may not move much if its just enough clearance for a gap when cold. If the exhaust is clamped one of the clamps could be loose but start with where is the noise coming from.How long has it been happening and is it getting worse on noise level, on how often it happens, or for how long it does it?

 

I have the same problem as long as my vehicle is cold. The problem stops as soon as the vehicle warms up.

I assume for me it's due to a lack of backpressure - free flowing exhaust.

I have 3" cat back exhaust with a flowmaster exhaust pipe.

 

The exhaust doesnt pop all the time I dont have headers and its coming from what sounds like the muffler area of the car. The popping is kinda like bang snaps (the things you throw at the ground and the snapped when you were a kid) , I do belive that the guy before me hollowed out the cat instead of putting in a stright pipe or replacing it, But once its warm theres no popping at all

I have the 2OTL cat back with no leaks

 

yep same thing happens here on my 97 ss....poparound the muffler area when cold....when it warms up its fine.....i have the slp slipfit exaust where it exits on the left.....im sure ur familiar with......just baught the slp loudmouth exaust...waiting to put it on though....see if it makes the same noise

 

Does the popping happen in the headers/manifolds? And on one side only?

Might be a burnt spark plug wire thats arcing, and the fuels detonating in the exhaust. Check your plugs and plug wires.

 

when was the last tune up?

 

in my case.....it's deffinitely not from the exhaust manifold. It happens at the rear.

I personally don't worry about it at all. I just let the car warm up first........should let it idle for a minute anyways.

I just had a tune-up done. Damn thing cost me $600.

I really think it's simply the free-flowing exhaust.

 

It is possible it is bad gas. On my 94 (which I rarely drive) I didn't drive it for months. I had the same gas in the take for probably 5 months or more. When I finally did drive it there were "explosions" in my Mufflex exhaust... pretty damn loud too! I believe it was unburnt crappy low octane worn out fuel finally igniting in the the exhaust. It would happen mostly when I let off the gas. I filled up with new good gas and the problem went away

 

It's nothing to be worried about.. my SLP 2OTL does that too. And my car is pretty much bone stock. I don't think it has anything to do with how well your exhaust flows because the 2OTL is right up at the top for free flowing. However I remember reading it has something to do with unburt gas igniting.. not very sure though... I bet it has something more to do with the metal expanding.

 

Every vehicle that has unrestrictive exhaust does this when the exhaust piping is cold. It's normal. I would imagine it being hot exhaust gasses being in a tight area that is cold with rapid velocity is what causes it. Either way, don't worry about it.

 

Not every free flowing exhaust does it because I have 3" mandrel bent with a flowmaster and no cats i've never had that problem I'll ask a friend that owns a performance shop and see what he says about it. I would say not to worry about it if that many cars do it.

 

Update:

I unpluged the air pump and the poppong has gone away, Since the cat is hollowed out I dont need the pump