2000 blazer 4x4 4 door LT.

A few weeks ago I had a P0171 (bank 1 system too lean) and P0174 (bank 2 system too lean) codes. I cleared the codes and they came back 1 time then the light turned off and they haven't come back since. The other day I got a P0102 code, I would clear it and it would come back on as soon as I would start the car again. So I pulled the cheap ebay cold air intake off and went to a junk yard and got an airbox that didn't have a big hole in the side, cleaned it out really well and let it dry, then put it on. Now the light still comes on sometimes but not as often. I cleaned the MAF with CRC MAF cleaner and it didn't really help. Sometimes the light will turn it self off but it will usually come back on within a few miles or the next time I start it. I drove about 200 miles today and the car only stumbled 2 times very briefly. Other than that it runs just fine. I was wondering if my MAF (about 2 years old) has gone bad or if there is another issue. I also checked and there are no other codes stored in the system. Any help would be appreciated.

 

P0171, P0174, and P0102, can all be set as a result of low fuel pressure and or volume. Before you go spending money, probably be a good idea to check pressure and leakdown at the service port, and at the fuel filter outlet. Post the results so we can see what's going on there.

 

I will rent a fuel pressure tester from advance some time this week. I was also thinking of replacing my fuel filter while I am testing the pressure at it, maybe this weekend. What would be a good one to replace it with? My local Advance has Purolator and ACDelco in stock.

I am also getting this, not sure if it just because I cleared my check engine light or not.

 

Before renting a tester I might just replace the fuel filter since it has never been changed since I have owned it for almost 4 years, and see if that helps at all. I am not 100% but I think my blazer has the quick release on the fuel filter, I would check, but it is pouring outside right now. Is there are write up anywhere on how to replace that?

 

2000 has a quick connect on one end. The other end has a 16mm flare nut on the line, and the hex on the fuel filter is 20mm. Use a flare nut, (line) wrench, NOT an open end, and certainly not vice grips! Hold the line wrench and unscrew the filter. Make sure you replace the brown O ring on the line, (brown means it's fuel rated, don't use black).


The "incomplete" on the screen shot means those monitors have not completed their tests. A drive cycle, done properly, will force all monitors to run and complete.

 

Use the line wrench on the 16mm? I believe I have a 16mm line wrench but not a 20. I haven't used my line wrenches in a long time so I forget what sizes I have for sure, i will try to get to it this weekend. Looks like the quick disconnect tools are pretty cheap.

 

20mm fits the filter, and that can be an open end wrench. The 16mm line wrench is for the flare nut on the steel line. Hold the line wrench & unscrew the filter from the flare nut. If you try to turn the flare nut, it might twist the steel line, then you have another problem to fix

 

Thanks! I will let you know how it goes.

 

So I ran a monitor on my MAF sensor yesterday while driving and the G/S was all over the place. driving down the street at approximately the same RPMs and speed I was going from 0 to 6.5 was the highest I saw. Then while at idle it was around 0 to 1.5. I thought it should be a bit more steady. Also Advance didn't have the o-ring for the fuel filter so I will swing by the GM dealer today since I will be right down the street. I did grab and ACDelco fuel filter since it was only $14.50 after coupon.

 

MAF is very sensitive and it will jump all over as the air intake changes with RPM. At operating temperature, in neutral/park, at idle, all accessories off, in closed loop, it should be 4.6 g/s. If you have the capability of checking frequency, that's a far more accurate way of checking it, (2285Hz).