smog fail Cali

[saleener94]

My stock 98 rs just failed. It had high hydrocarbon reading of 99 and max is 43 at 25mph. I seafoamed the fuel tank days ago. I've already looked for vacuum leaks, bad spark plugs, wires, they are all good. The car does have a Dynomax muffler and I heard some rattling inside couple months ago that has since settled. When I looked in there it looks rusty, wet and pieces inside look broken. Is a muffler suppose to look like that inside? Another thing that I'm suspicious of is it stumbles at about 1500 to 2000 RPM intermittently. When it was getting tested, I could hear the car stumbling at low RPMs then smoothing out as the tech accelerated. Any ideas what can cause that?

 

[GSLENK]

probably ignition. check spark plugs/gap, wires, etc... a stumble is caused by, bad fuel, air, or spark, or tune, which I doubt you altered your tune so you can throw that out. Spark is typically cheap to replace, so is air, then fuel. check in that order.