1998 Chevy Blazer Service Engine soon light

It isn't the gas. What I need you to do is take the vehicle to a nationally recognized parts store and have them scan the computer. If the light was on, there will be a code stored in the computer that will help identify where the problem is coming from.

Let me know what you find, the code, and don't let them sell you anything until you speak with me.

Joe

PO 102 - Mass or Volume Air Flow Circuit Low Input

I would recommend that you clean the MAF sensor and see if that helps. You will have to remove and disassemble it, then VERY carefully clean the elements on the sensor with MAF specific cleaner. Here's a picture:

You can faintly see the elements I speak of. These elements should be whitish silver in color. First, attempt to clean them with just the stream from the aerosol can of cleaner. If that doesn't work, you may have to spray some cleaner into the cap and use a q-tip to clean the stubborn grime off, but this is where you have to be VERY careful as the elements are fragile.

PO113 - The intake air temperature (IAT) sensor indicates the temperature of the ambient air that is entering the throttle body. The IAT sensor temperature should read very close to the temperature of the outside air. The IAT sensor temperature should rise gradually as the engine warms up and the underhood temperature increases. This code could be set as a result of the
MAF code. Start with that to see if it helps. NOTE: This code will eliminate itself after temp readings are correct for 2 consecutive start ups.

PO440 - First, make sure that the cap is on tight (3clicks) then you could have an Evap Emissions failure. Also there is a pressure valve on top of the fuel tank I think in the same assembly as the fuel pump. If this valve fails and the computer commands a test for the Evap Emissions system it can set a code.

We need to do one thing at a time. Start with cleaning the MAF. It is on the air intake tube from the air filter. Remove it and clean it with the proper product.

Let me know if it helps.

Take it to a nationally recognized parts store and have them scan the computer and then reset it. Make a note of what codes are listed.

See if the light comes back on. If it does, have it rescanned to determine if the same codes came back or there has been a change.

If we end up with an EVAP code and you smell gas at times, you need to have the EVAP system fogged to check for leaks. THey will actually fill the system with fog and where is a leak, it will come out so they can find it.

Let me know what you find.
Joe

If the fuel cap's gasket is cracked or broken, it will allow pressure to release from the system thus setting the EVAP code. If the cap doesn't take care of it, let me know.

Joe