Hi. My brother in law has a 01 blazer. It was running weird and rough so he took it to firestone to be fixed. Got his truck back and 2 days later he is broke down again. This time they two it to firestone. I finally heard about it and flipped out why are you paying them too do stuff we can do for free. So I called firestone asked for codes and what was wrong with it! The give me codes p0131 p0171 p0174 p0300 p0463. I have been looking online for answers and can only find answers too some of the codes I am planning on checking g it out Saturday and Sunday but would like recommendations on where to start. As far as I can tell it sounds like a faulty fuel pump/air leak/maf. Sensor any help is appreciated thank you have a great day.

 

Unplug the MAF and drive it. If it runs better, that's likely your problem. Also check the fuel pressure.

 

Thank you will test maf sensor tonight and was already going to check fuel pressure tomorrow. The shop he took it too is adamant the o2 and maf sensors are bad and the fuel pump also. Plus a list of other non relevant issues. I have not heard of all things going at the same time has anyone else?

 

Ok so I unplugged the maf sensor and had no change at all not 100% sure what this means as there are conflicting reports online but I am going to clean and change any ways. The fuel sending unit is bad this I know because the fuel level on gauge is been incorrect since he got the vehical so will be changing that. Not sure that needs to be done right away though because it has never worked and drove fine so doing that last. Also may need o2 sensor but wont know until maf sensor replaced or cleaned. Anything else I should do let me know thank you for the help.

 

Sounds like the MAF is probably fine. How was the fuel pressure?

 

Here are all of the trouble code diagnostic charts if you care to dig into them:
I would ignore the fuel level sensor code for the time being and get right to testing the fuel pressure testing. You very well might end up correcting the P0463 with a pump replacement if that's where the fuel pressure & leak down test results take you.

 

Have not got to test get auto zone already loaned out the test kit. It was supposed to be back today but has not been returned yet. So I am waiting on it

 

Is there another way to test? Also the air filter cover was only half way shut

 

Ok so I tested the fuel pressure came back at 52 idle 60 with acceleration. I also changed the maf sensor and o2 sensor because the shop quoted him 1500 for all three things he said he would spend the $300 on new parts to have it running right away. So I am waiting for light to come back on recheck codes if only p0463 comes up then may wait to change pump if more will change a.s.a.p. thank you for the help and advice.

 

Hey blazer fans,

So just bought 2002 blazer with 4.3 from PA. Thing is pretty much mint. As i so aptly found out i had a p0442 small evap code, i replaced gas cap and it turned off code. Almost instantly got p0300 randon misfire. i knew the vehicle just had new distributor cap and rotor replaced and also had new spider injector replaced. the vehicle was not running rough or backfiring, had no loss of power. so i thought what the hell? wasnt fuel pressure problem. so just out of curiousity i found out the retaining screw on the firewall side of distributor cap hadn't been tightened down at all i could just about fit finger between cap and rotor also found out this 4.3 while having individual wires and plugs also has a solo ignition coil, commonly referred to as pick up coil, with the ignition control module attached right to it. so, in my drunken stupor and curiosity, i unplugged the wire that connects to the coil from the distributor and cleaned both the wire connection and the coil connection with qtip soaked in 91% rubbing alcohol then squirted a bunch of dilithium grease into coil connection and reconnected wire from distributor moving it around a little to spread the dilithium. then added can of seafoam to gas tank and filled 93 octane. Drove it for a while. found a couple different straight aways and just ****ing punched it then parked it let sit at idle and code p0300 turned off on its own. also worth noting i waited till night to check plugs and wires for arcs in the dark didnt see a goddamn thing. i think the pick up coil is often overlooked