Odd ignition sound

[Smokin' Rubber]

Around 2 weeks ago maybe a bit more the sound my car makes when it starts changed. Before this period it would maybe cycle once and the engine would have a nice smooth pur start like (chwom bruuuuuuuuuuuum) now there is a like hiccup right after the engine actually starts so it doesn't quite sound smooth anymore more like (chwom bruuu ruuuuuuuuuuu) Maybe somehow the ignition timing got changed? I don't remember doing anything to my car in the time that the engine noise changed tho... and the car actually seems to be running better if that is possible, after the car starts it seems to run smoother and have alittle more giddyup altho could just be my imagination.Anyone have any ideas as to what could be going on?

[pa-vibe]

How long ago did you put the exhaust and intake on? From what I understand the ecu tunes itself during driving. This can take awhile before any thing is noticed. This may be the reason GM instructions the sc users to drive for so many miles before taking notice of perfomance changes. Anyway is seems possible that the ecu has changed it's stored info?

[futseal04]

Also, how many miles does it have? Maybe you need to run some fuel system cleaner through it to clean the injectors or change the fuel filter.

[Smokin' Rubber]

It's been like a year and a half since I bought it (Jan 03) and it only has around 9.5k miles on it. As for the exhaust and what not they were installed around 3 weeks ago it think maybe moreOh and on a side note I suppose the wierd ignition sound only started happening a week ago so there was 2 weeks where it was normal sounding with the exhaust/intake.