Smooth08LTZ

Got a 2000 silvie that runs ruff at start up and slightly less ruff after. I have changed plugs, wires, and ran 2 treated gas tanks or fuel through it with no change. Had a hole in the muffler and replaced the flowmaster (for free..nice to have relitives that know the owner of flowmaster...shamless plug) with no difference. A different reletive works at a dealership and suguested changing the o2 sensors (2). Anyone recond that will clear it up? I hate to burn $100+ for 2 o2 sensors and get no change. It's the wifes silvie.....she loves me and let me drive the 08 LTZ.............for now.

jmack91z28

If its the O2 sensor it should be giving you an engine code.

When was the last time you changed the fuel filter?

Smooth08LTZ

replaced the fule filter about a month ago and no codes have ever came up in 8 years except the change oil light.

ukrkoz

O2 sensor is not part of your fuel/ignition system, but part of emissions system. the only adverse influence onto the engine is reduced mpg, maybe slight power loss. don't waste $$ on guessplacing - replacing on a guess.
running rough goes down to several issues: fuel supply or ignition/elkectrical issues(with timing being into it).
let me look up a good post for you, i have link to it on my work computer, if i find it now - i'll add it to this post.

not quite the right article, but stll, a good resource:
http://autorepair.about.com/cs/troub...a/bl303a_2.htm

i'll have to attach the "no codes" one tomorrow, i guess, as it is very specific on what tests need to be done when handling no codes situation. pretty much, it all goes down to checking fuel pressure, ignition system, and EGR valve, which the last one can do hesitance and stalling.

ukrkoz

here's the promised article:
http://autorepair.about.com/cs/faqs/l/aa042603a_1.htm

Smooth08LTZ

Thanks for the links....I'll go through them and see if I can get the 8 yearold running right. I'm wiith you on the guessreparing.....I have an 08 to pay for and it is breaking me on the gas for both silvies that are daily drivers and it's too damned HOT to ride the bike.

ukrkoz

happy hunting, smooth.
well, it's either hot to ride a bike, or expensive to drive a rado. i, personally, am starting mixing my 4 cyl ranger into the daily commute. i could pull 28 mpg off it summer time with special fuel additive. definitely not as comfy and safe as rado, but hey - it's only 1 hr a day spent in it.
don't ask, i tried, chevy does not respond to the additive.
let us know what you found, we all learn off this.