Hello

I just purchased this 2k2 blazer a couple days ago. The service engine soon light came on. I also noticed the gas was wasting rather quickly. So I went to Advace parts and ran a Diag on It. It came back with reading p0171 and p0174. I researched this and found a fix would be to clean the MAF Sensor. I did that and it made a world of difference. The truck runs like it should, its not idleing high like before and after just running it today the gas seems to be alot better. But the was earlier in the day. In the after noon Service light went off for a couple of hours and then came back on. Also now it Idles a bit high right after take off and not long after, it start to operates just fine again. Also not sure if related or not. I have a slight knocking sound that does a fast repeated knock for about 30 seconds every once in a while when I start it up and then goes.

Some research ive done now points to replacing the PVC valve for the issue of idleling high and the service light.

For the knocking what I am hearing is that it could be the lifters. To replace the Oil and Filter.

Anyone have any suggestions for me. I am trying to solve this myself before taking it to a Mechanic plus I kind of like this whole fix it yourself stuff, as Ive never been mechanicly sound but I like it. Thanks for your time..

By the way..the truck reads 71,000 miles. It looks great in and out. I love it and would love to keep it..lol

If the SES light is still on, have the new codes read and let us know.

Definitely get the codes read again.

As far as the knocking sound, that doesn't sound too good. Lifters are rarely described as a knocking sound. More a metallic ticking.

You may want to remove your throttle body and clean it. The IAC (idle air control) valve controls idle speed when the throttle valve is closed.

What did ya use to clean the MAF sensor?

I used CRC/contact cleaner. I got it at Advance, it says on the bottle MAF cleaner, its really good.

Hey Guys

I went ahead and got another reading. I am still getting the same reading..p0171 and p0174. We cleared the reading and now I will see if the Light comes back on. Although the truck still idles a lil high when going from first to second and then it drives OK. The truck is automatic.

I just bought the OIL, oil filter, and belt. Going to replace it today. I replaced the air filter yesterday.

I am also going to use a product called SeaFoam..Has anyone used it or recomend it. http://www.seafoamsales.com/motor-treatment/index.html

Ok, i was just making sure ya didn't use just some random cleaner (they will ruin a sensor pretty quick) These codes are caused from a lean condition. When ya take the PCV valve out, give it a shake, if it rattles it's stll good.