Hi, I've owned my 98 Blazer for 5 years and the truck has been great. I'm in the process of trying to sell it, but have been having trouble with the check engine light. I boughta Trailblazer in November and haven't been driving it much lately, but need to get these problems cleaned up. My Blazer has 182,000 miles with 100k on the 4.3 Vortec.

I have replaced the cat and exhaust last spring and replaced the fuel pump and fuel filter shortly thereafter. The check engine light started coming on last fall. I've had the intake gaskets replaced, water pump, and all 3 O2 sensors. Each time I have it into the shop, he clears the Bank 1 sensor code (lean)and I'm good for 2-5 drive cycles and the light comes back on. Every time, it comes back on at idle at a stop light after driving for 45 minutes (my morning commute). My mechanic is baffled and I'm looking for more ideas on what to check without spending a bunch more money as I'm trying to sell this. It runs fine and has no tranny trouble or anything. The only problem I can report is a little excessive cranking on startup (which I'm told can come from the aftermarket fuel pump that was installed last sprint).

Any help would be appreciated. Thanks!

 

Doesn't an air supply problem cause a too lean code? That would explain the problem taking a while to build up, and then it comes on at idle when there's no pressure to force the air in...

Dirty air filter...MAF issue....something in there?

And what caused you to need a new engine after only 82k miles if ya don't mind me asking?

 

I'll go out and check the air filter right now. Its probably been a year since I've done that.

I bought it in '02 and the dealer told me that they had put a new motor in it. I was told that the owner had hit a deer and proceeded to drive it without a radiator until it basically blew up. There wasn't enough damage to total it, so it was fixed and I bought it with 16K on that new motor.

I'm a little sad to be giving her up as she's been a great vehicle.

Thanks,
Becky

 

By the way, my Blazer looks just like yours without the bigger tires and roof rack but with running boards.

 

Black or chrome bars? And are they bars or boards? I might try to convince you to sell them if they're black bars

 

Sorry, they're black boards. Probably notthe look you;re going for .

Called my mechanic just now and asked about the air filter and possibly a bad cat. He said that I had plenty of air flow on both sidesand if it was something like MAF or spider that I should be noticing power loss and/or missing, which I'm not -- and therehaven't been any misfire codes storedeither. The mystery goes on...........

 

Can you tell us exactly which code numbers are being thrown?

 

Sorry, I don't know exactly what the code is - just P something. I just asked for the translated version of the code - emissions code for the Bank 1 sensor.

When I get it scanned again I'll ask them exactly what the codes are.

I think I have a guy coming to look at it today and have his mechanic give it a look over so maybe I can work something out with him price-wise since its still running good. I know most vehicles mines' age have an almost permanent Check engine light [&:]. I'll have him get the codes for me if he does take it in.

 

There are many problems that can trigger many different O2 sensor codes. Really need to know the specific code before recommending proper diagnosis as riddle has already suggested/asked.

I can say one thing... From the sounds of it, your mechanic has just been throwing parts at the truck at the expense of your bank balance... Next time the check engine light returns, just take it to Autozone or Advanced Auto to get the codes read and let us know what the specific code is.

 

Next time I have it scanned, I'll post the codes.

The only parts I think he may have just "thrown" at it are the 02 sensors themselves. I know that the intake gasket was bad as I had an antifreeze leak without a puddle, then shortly after that I had a leak coming from the water pump itself (cracked), so that was replaced. I know the exhaust and cat were bad when those were replaced also - it was plain to see and hear on that one.I know the fuel pump is the repair that was needed the day that it went out. To my knowledge, that original fuel pump went 150k miles. I know the reasoning behind replacing those sensors was that the antifreeze running through the motor from the bad intake gasket fouled them so badly that they couldn't be cleaned up enough to read correctly. We replace the upstream two first and when the light came on again we replaced the downstream one.

Thanks for your help.