lts_Mr_Yum_Yum

I purchased a 99 GT recently. Car is completely bone stock besides a CAI and a Magnaflow Magnapacks exhaust(worse exhaust ever btw, don't buy it). Anyways, at idle my car's exhaust is making a little "puff" noise. It's not like a pop it's like a little "puff" and it happens every couple of seconds, sometimes it'll even puff 2-3 times every couple of seconds.

I don't know if its misfiring or timing.. Car drives perfect on daily driving like scenario. When I try to get it on, after like 4k Rpms it like bucks a little bit then the power like immediately kicks in. It's hard to explain.

FrostByte

Coil paks?

FlamingoGT

Have you checked for codes, even if you don't have a CEL?
Have you checked the plugs? plug boots? Plug boots can develop intermittent leaks... couple bucks each, so is very inexpensive preventive maintenance when you do a plug change.

SXGT

my 97 did that. I determined it was running lean. and it was a puff because it wasnt getting enough gas in the combustion chamber to make an "explosion" it was a small vacuum leak.

lts_Mr_Yum_Yum

I do have an Engine check light. And when I went to check it out it said the car was running lean? But I have no issues with idle. It idles perfect. The only problem
Is at idle there is a "puff". Also when I floor it, the car sputters.

I'm probably going to change all spark plugs, and ignition coils. Now I'm scared to remove those plugs...... I've heard they are a nightmare and I'm
Terrified

SXGT

was the CEL about the Evap purge?

FlamingoGT

It's not that bad... just make sure they are started straight and torqued properly. There is a pretty decent write up in the how to section, and some tools that can make the job a lot easier.