The original engine was running great until the intake gasket blew and the engine overheated causing the head gaskets to blow. Since there were so many miles on that engine we decided to go with a Jasper engine. It never was quite right. It started making strange noises and misfiring. It seems that the cam bearings were no good, on the new engine! Now the "new" new engine seems to run so much better than the first new engine ever did.

We also have another problem. I posted a different thread about vents. When the AC/Heat are off and the fan is off, hot air pours in through the vents. Also, when the air is on and I accelerate, it seems that the air goes somewhere else or the fan slows down, not sure which. When I let off the gas, the air comes through the vents again!

We did change the O2 sensor before taking it to the shop. They said it is functioning fine now, so that code seems to be clear. Now, my check engine light is blinking, then steady for a while, then blinking. I took it straight back to the shop.

I looked under the hood before taking it to the shop. I am trying to post an image, but there is a small hose on the drivers side beside the brak booster that is attached to a plastic T on one side and just dangling unhooked on one end....

 

 

There is your vacuum leak. Bet that will fix both your P0300 and your HVAC vent problem. I would let the shop hook it up so they learn something. Let us know!

 

I am trying to add an image. This hose goes to a sensor, right? Lesmyer, thank you! I sent the mechanic the image. The hose is new. It seems that either the bracket it attaches to is broken, or they failed to hook it up. I will let you know what happens when it is hooked up correctly.

 

Here look at this video that I found. Goes to the vacuum reserve canister in the fender.

 

Was not the vacuum. It seems that my distributor was bad. They replaced it and the cam position sensor. It took 40 times to sync them. Is really the distributor, or is my computer bad? The sync should have taken 5 minutes.

 

Actually you don't have to do a crank relearn after replacing the distributor (which houses the cam sensor). Rev up past fuel cutoff 40 times? Ouch! Must not have been doing something right with the procedure. I know you have to clear any codes immediately before, and set the park brake enough so brake light comes on - then hold brake pedal down when triggering the procedure. I believe if you run it long enough to let the full misfire code reset and SES light come on, then you have to shut engine off, clear codes and start the procedure over.

If it's no longer setting a PO300 then I suppose it is possible it was the distributor, but in reality I bet they never completed the crank relearn successfully before (look at how much trouble they had doing it) - you will never know for sure. I wouldn't worry about the PCM.

FYI recently my new engine was PO300 and SES light on pretty much constant until I made it though initial break-in and relearned the crank sensor. Mine took the relearn first try when following what I said in paragraph above. Your results may vary.

But as long as problem is gone, and doesn't return - then I would certainly accept the results!! Hope you didn't have to pay too much for the distributor/installation. It's not a bad thing to have! With the PO300 fixed you can expect even better peformance and mileage, even if it wasn't really missing before. Now your TCC will work.

Thanks for letting us know. Congrats! Did the vacuum line fix the air out the vent problem?

 

Lesmyer, the thing is, we took it to the shop about 3 weeks ago with the P0300 and flashing SES light. That is when they discovered the Jasper engine that was installed 18 months ago was bad. After they changed the engine, the P0300 came back. That does tell me there was a problem before the re-learn. And yes, the vents are now fixed! They are only charging me parts and labor to change the distributor and sensor. They are not going to charge me "check out" since they have had the Blazer for so long. Actually, I think you posted a bulletin about the distributor causing misfires on 2001 - 2003 Blazers which made me think they were finally on the right track yesterday. It hasn't misfired today. The shop manager is driving it home today, and then driving it more tomorrow to make sure it is fixed. Thank you!

 

Looks like they are trying hard to please! Best wishes!

 

Well, I picked up the Blazer. The mechanics drove it yesterday and the P0300 and misfire are gone. They start her up to bring her around and the SES light comes on AGAIN! They scan it, and the P0135 is back, but thankfully the misfire is gone. We replaced that sensor ourselves with a Bosch. Should I get an AC Delco? I know my blazer does not anything except Delphi and AC Delco parts (believe me, when we have used anything but AC Delco or Delphi for the Idle Air Control, Distributor Cap, and ICM we have had to take the part back and find the AC Delco or Delphi). Any suggestions?

Also, the vacuum canister line that was not hooked up, well, they didn't hook it up! They put a plug on the end of it to close it up. I am going back tomorrow and stand there while they hook it up