1996 Blazer 4x4 Trouble: Lacking Power and p0133


Old 04-23-07, 02:17 PM
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1996 Blazer 4x4 Trouble: Lacking Power and p0133

1996 Blazer LT 4x4 4.3L v6 135,000m

The code is p0133 for o2 sensor.. (lazy sensor, bank1, sensor1).

Would like to know which sensor is the correct one to replace.From what I have read, this one is supposed to be on the drivers side. I just took a look and I can see one sensor pretty much right underneath my drivers seat about a foot down from where my exhaust connects to the engine...and on passengers side there are two others before my cat.

First I'll start out by saying I got what I THOUGHT was a great vehicle about 6 months ago from a dealership. Ran great for maybe 4 months, then I noticed a lack of power/ bad gas mileage! (felt like it was running about 80% of the norm ). Could smell it running hot, so I had the radiator flushed out which looked like it had never been done before to me :/ and I changed the fuel filter, and ran some fuel injector cleaner through a tank of fuel.

This seemed to help for about a month and half, then I could smell the engine running hot again and felt the lack of power (again running about 80%). Radiator cap wasn't holding pressure ( was only a few months old) so I put a new one on, and it would let just a small amount of my coolant seep out once the engine warmed up. Did a test for combustion gas in my coolant, and it was a negative. Did the radiator flush myself this time (dipsticks at jiffy lube didn't even put the correct amount of coolant in), and had a tranny service done. Again, this seemed to help for about a week, then **** really hit the fan.

Engine power felt like it was running at MAYBE 50-60%, would have to downshift it out of overdrive to get up small hills on highway very sluggish acceleration..was just brutal. Took out all the plugs and changed them. The plugs looked like the engine was running just a little lean..except the one in the back left cylinder was worse than the rest. After doing this it took me back up to about 70-80% power.

The smell persisted, I replaced the thermostat to make sure it wasn't sticking at all. Flushed radiator AGAIN.

Now, the truck is up and down as far as the power goes..One minute it will seem like its maybe running 80-90% of the norm..and the next it will drop down to maybe 70%.

P0133 Popped on again last night (I knew it would since I didn't replace the part the first time about 1000 miles ago)

I am guessing that as a result of my o2 sensor being "lazy" im getting a bad fuel/air mixture and that is whats been causing causing my lack of power...Maybe Jiffy messed up my tranny fluid level(wouldnt surprise me). Would it make that much of a difference if they put too much fluid in?

Trying to sell this thing so I can move, can't sell if it aint running well!! Any help is appreciated.
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Old 04-23-07, 03:00 PM
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Red face lack power

I think trannys have a blow tube that release excess fluid just in case. Did you consider a stuck open EGR valve? I dont know alot about O2 sensors but I did hear they can become fouled with gas just like a spark plug. Anytime I ever have any concerns about engine power I always head to the tailpipe first and inspect what is coming out, whether it is hot, warm or cold, whether it comes out clean smelling or burns my eyes, if it smokes, drips any fluid, makes any noises, even if it sucks in a dollar bill or misfires or anything that gives me a clue to what is going on inside that combustion chamber. Then I'll go to the intake.
Old 04-23-07, 03:45 PM
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I pulled off my EGR to get at my thermostat, and everything looked fine inside of it. Not too much buildup, and I would think the engine would give me a trouble code if it was the EGR..The vehicle has lacked power for close to 12000 miles or so now, my guess is that the computer could pick it up if that were the case.

I understand the o2 sensors are what sends the computer info on how to do the fuel/air mixture. With this sensor givin a slow response (bank1, sensor1), could this be the cause of my vehicles slow acceleration and lack of power? Also any info on where its located ( i think its the one right under my drivers seat, and not either of the 2 before the cat on passenger side) would be appreciated
Old 04-23-07, 06:30 PM
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96 blazer

with all the trouble you have been having with this have you ever checked fuel pressure or does it start hard? Good places to start When you replaced the spark plugs did you put the correct ones in or the cheap ones and did you gap them correctly. Also check out the cap and rotor the may need to be replaced, The O2 sensor would not cause you to have a lack of power like yuo describe check the other stuff first and also replace that sensor and get the code cleared

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