Back again with yet another set of problems and codes. It seems to be a never ending occurrence with my 1998 5-speed Blazer, and she's 151,000 miles now.

Currently I'm having the codes P0131, P0151, and P0143, and occasional P0440 but only if I screw my gas cap in. Don't understand the 440 code since my fuel pump is maybe a year old, but it could've been a lemon yet I'm getting pressure. So much that if my gas cap is screwed on tight, when I unscrew it a gasping vacuum noise is emitted. Thought maybe a blocked line with Evap or such, but maybe someone here can tell me.

As for the exhaust O2 sensor codes, lately after long highway drives of around 5 hours, I cease the ability to downshift and rev over 2.5-3.5k rpm. It just limits me, starts sputtering and backfiring, but only under WOT passing or such. Seems okay if I lightly press the throttle. Thought maybe my cat was plugged up again, yet that's only a year and a half old itself.

If anyone has any bright ideas of what to look at first, it would greatly be appreciated. This Blazer has me mind boggled all the time.

-Ballysto

 

So I wonder what clogged up your previous cat in the first place? After 18 months it could indeed be clogged again. Have you tried taping a fuel pressure gauge to the windshield and driving around until the "rev limiter" kicks in?
Does your temp gauge stay at about 200 degrees when fully warmed up? If not then you may have a stuck open thermostat... hence the cat clogging problem.

 

Haven't tried taping up a fuel pressure gauge, but might try that. If I'm having intermittent problems then I must have wiring problems galore. Sometimes when not even in gear, I'll rev up open throttle and let off, and it will stay at 3k for a minute or so and then finally drop. I've checked my throttle cable, TPS, IAC, all of those and they are fine. I've cleaned everything as well, vacuum lines are fine, and I'm stumped. Unless my clutch has a problem.

Here's a youtube video of that issue: http://www.youtube.com/watch?v=aK6kfKjquzw

But tonight I flushed my coolant out and it was pretty nasty, so got that all cleaned up in hope of helping something. Started it up after cleaning that and my carbon buildup, started stuttering and backfiring about to stall, but never did, took it for a test drive and it seemed fine, revved over 4k with no hesitation. Came up with a P0118 (Engine Coolant Temp Circuit High Input) and it's been doing that lately as well, but I figured it was a loose connection because of the fact that sometimes my temp gauge would not read, got some stress off the wires and it reads correctly again, yet still threw that code so I don't know.

If anyone has some ideas, throw them my way!