Hey guys, new member here, and have been reading these forums for ages now. I've got a 2000 Blazer 2 Door, with the usual 4.3 V6, 2 wheel drive, etc etc etc. It's had it's share of problems, but something new has risen.

I noticed a few years back when I gunned it going up a hill, sometimes it would drop into "passing" gear and rev relatively high and seem like it had no power. Service Engine light would begin flashing and once I drove it a few minutes at normal speed, it would be fine. Noticed about a year ago that I had slow rising exhaust smoke at night, whether it was summer fall or winter nights, and that the exhaust smelled gassy. So, that brings me to tonights post:

Earlier the engine was doing the usual SES blink going up a large hill, so at the top I threw it in neutral and revved it up. If I lightly rev it and don't open the throttle all the way up, it will "red line" (didn't push it that far, trust me) just fine. However, if it's about 5500 rpm or so and I floor it, it'll bog back down to about 3500 or 4000, and if I keep it floored or so, it stays between 3500 and 4000 and won't rev any higher unless I back off the throttle.

Now, for a while, back when I first got it, the catalytic converter was rattling like HELL. I did run some codes last year (right before it stopped rattling) and was told the cat needed checking and that it was sending back an error code. SES light has been on for a few years now but no codes could be found until the cat codes posted last year. I do know how crazy that sounds because I know from previous vehicles I've had, if the SES light is on, there's an error.

I've noticed no drop in coolant, I've maybe topped the reservoir off 5 times the entire time I've had it, the heater works fine, the A/C does not, but what bothers me is the gas fumey exhaust and the revving not wanting to go over 4000 when I floor it. I'm praying it's not a head gasket as I've already replaced a thermostat and intake gasket. It warms up to about 210, if not a little more, but the smoke at night is like condensation. It's not really a color, just a smoke that slowly rises.

I've never noticed another vehicle smoking like that unless it was super cold.

 

So did you replace the cat or just ignore the codes?

Flashing CEL = misfire:
P030x - Random/Multiple Cylinder Misfire Detected

Have you tested the fuel pressure (see link in signature)?

 

Your exhaust is clogged at the back end of your cat or muffler from the broken garbage inside your cat. First, go to the muffler shop and recycle your cat. They are worth about $75 for the broken 'honeycomb' inside, due to its metal content... Get a high-flow cat welded in and be done with it ($150) or get one that bolts on from salvage that is intact- if you can find it. They dealership wants $750 for the part... Second, replace your O2 sensors. ($50 each)

 

Typically, a clogged exhaust due to a failed catalytic converter would result in a sulfur smell (rotten eggs is the most common description) along with the motor reluctantly revving, not free revving with a 'gassy' smell.