PO300 problem solved
 

I've got a 2001 mc SS. Just updating, but I have had a po300 code for 3 weeks since I got my engine block swapped out. This was the only code that I got but it wouldn't tell me where it was misfiring. I went to the dealer today, to get it diagnosed, I had heard about the crankshaft position system variation learn procedure, I provided the service person with the info because I had read that some dealerships didn't know much about it( which he didnt). It cost me $99.30 to get this done. Before I could even see me car the guy came back and said that it didn't work and that I was still have a misfire in cylinders 4 and 1. So this guy came up with some outrageous quote of a $1100 to fix it right. He want to replace the icm and all 3 coil packs. I had found out were the misfire and that was all that I needed. So I just paid the 99.30 and went to go get the car. When I crank the car no check engine light and it running and sounding good. So I'm like wtf, this guy told me that it didn't work, but everything was running fine. I just replaced the coil pack for the cylinder 4 and 1 and now I'm back in power. I said all that to say if you have changed your engine, the crankshaft, or pcm then you might want to read up on this.

Thank you very much for the valuable info! I'm sure you're going to save someone a $1100 repair bill. The $99.30 sounds like a one hour labor charge.

Glad to hear your Monte is back running again!

Thats why I love this forum, because you can pick everyones brain. They charged me $99.30 for the relearn procedure its self. It actually only took the guy about 10 minutes to do the job once they took my car back but I had to wait like hour for them to do that. I really didn't know if this procedure would fix the problem, but it did. So guys and girls if you have to go to the stealers then I would suggest you research your issue(s) and then what you can't do yourself take it to them. Make sure you know what you want to get done, because if you depend on there recommendations then your screwed. I mean its crazy how this procedure made my car run better and fixed everything but the guy tells me that it still didn't work. Comes up with some crazy recommendations and want me to fork over $1100. I hate going to the dealer but I guess they are sometimes a necessary evil.

I assume you referring to a case relearn?

Curtis, you're absolutely right. Sometimes the dealer is a necessary evil. If the dealerships around you are anything like the one's here, they have a minimum one hour service charge. Which kinda sucks if it's something that only takes 10 minutes. But sometimes if they're really nice, they'll let you slide on something really quick and easy.

My dad needed a new battery in his car. Brought it to the stealership. They popped the old one out and installed the new one in 5 minutes. Only charged him for the battery. Let him slide on the labor charge.

Glad your Monte is back running. And it only cost you $100, and not $1200.:thumbsup:

Update, I might have spoken too soon, my car is running, the po300 code is gone, but the car still is running funny. I have no codes, but the car has a ruff idiol and drinks gas like a suv. I also here a ticking sound from the back of the motor when I hit the gas from 1st to second. The guy told me that I had a misfire in cylinders 4 and 1 and that they had misfired over 4000 times according to his scan tool. He said that I should get new coil pact and a new ICM. Now I'm just trying ot figure out what is causing the misfire. So far I was only able to change out the wires to see if that was it.NO. I rotated the one of the coil packs and nothing changed. Still runs the same. I have also been having an issue with the car starting whenever it wants too, but that is for another post. Does anyone have any ideas on what is causing the misfire in cylinder 4 and 5? I want my car to run like a champ again.

Do a compression test, head gasket could be going bad. Also check your fuel pressure

Other than that, could be the MAF, crank sensor, ICM, coils, or a combination of other things. Change plugs, wires, fuel filter

You said that the misfire started at the time of the engine block swap. Who did the swap and why wouldn't they have some responsibility for determining if the problems are related?

Have you installed new plugs? One could be bad or cracked following the block swap.

How bout the injectors - could that cause a misfire?

Gotta be spark or fuel - right???

Could this be a grounding issue - just thinking maybe a grounding strap is off or missing?

So far I have changed the plugs(ACdelco) and wires(duralast wires). I don't have any codes though. Would one of these trigger some sort of code? Do you know how much a compression test is? The car runs ok just not the best it could be. It has a rough idle, drinks gas, and when I hit the gas from 1st to second I hear a tick, tick, tick..., like I can her the spark plug firing or something. I checked the spark plugs for the ones that the dealer said had a cylinder misfire, they looked fine. Could it be an issue with the plugs, they are brand new? Im at aloss this car is driving me crazy, this is just one of the things that is going on with this car.