02'Pontiac GP won't run over 3500RPM

[Arc Burn]

3.8L with 64,000 miles,auto trans just changed fuel filter.Car just bogs after 3500 rpm and won't shift up either?any ideas?

[Arc Burn]

SES light flashed rapidly 2 different times in the past month while acting up but computer has no stored codes for it?

[Pickering Snow]

Two things but ill put myself out there on the first. 02 Grand Prix's and Chevy Impala's have aproblem with the Cat converter neck collapsing causing intermitt no power or can be all the time. GM has raised the Warr on these models to 10yrs 100k mile warr on the Cats.

The other would be a bad plug wire causing not only the affected cylinder but its paired cylinder to cause severe missfire hence causing the Flashing Ses light. My bet is the Cat i use a back pressure gage in the 02 sensor hole to verify but honestly if shes just flate no power i would bet the converter neck is collapsing on acell.

[Arc Burn]

Thanks Fred.If you follow the exhaust from the manifold back to the cat,there is a small section of pipe that is not round,it flattens out,not closed but just not round either,is this the spot?
I'm doing plugs and wires now also as 2 plug boots ripped from the wires while inspecting plugs which are burning hot i might add(white electrode tips on all 6 plugs)which makes the cat problem make sense now.

[Arc Burn]

You nailed it Fred.Cat was collapsed,We called GM with the VIN# and it's all covered.I would have replaced the Cat myself had you not mentioned that($300+)I owe ya one buddy:drinkup