hey there new to the fourm just wondering if any one else is getting the bad of mileage and any ideas how to fix it tried o2 sensors and air filter dont wanna just start throwing parts at it also 4wd light is on no clicking when button is pushed but vacum at the actuator under the battery not sure if this has anything to do with it.

 

for got to add this is my girlfriends blazer says there is a smell only sometime never smells when i drive it and gutted out the cat thinking maybe that was it mileage picked up to 175miles a tank lost and confused what else could be wrong?????????? any ideas greatly appreciated

 

as just informed that the ses light is no p0420 came up when i scanned it only changed passager side o2 senors up and down stream. Only one left to my knowledge think thats it or something else.

 

po420 is catalyst efficiency. aka your gutted cat. Pull a few plugs and look at em. Chances are its just time for a good tune up using only ac delco parts. (ngk plugs are ok)


Replace the cat,and do a tune up and get back to us. Not much we can do if everything is worn out.

 

Not having a cat isn't going to kill your mpg like that. The downstream o2 sensor only tells the computer if the cat is working correctly. It has nothing to do with the air/fuel mixture. I would do a fuel pressure and leakdown test. Chances are you have either a leaking fuel pressure regulator, or leaking injectors. You can also look down the throttle body with a flashlight. If it looks really clean, you know there is a leak ( it should look black and sooty).

 

Check the vacuum lines, they're probably off somewhere & or cracked. They could also be causing the 4wd issue. Having fluid in the vacuum line to the tranfer case could cause it too.

BTWcouldyoumakeiteasieronustoreadbyusingsomeformof punctuation?!

 

Gutting the cat wouldnt hurt my mileage. Plugs look brand new checked them already.
As for the 4wd checked all that leaning towards the tccm. Cause when i hit the button it sucks the vacum flashes a few times and releases the vacum.

 

Cause the code came up before i gutted the cat out. Reason for gutting the cat=code p0420 figure cat was pluged. guess not. lol Gonna try fuel pressure test what should it read at the regulator??? How long should it hold pressure 10mins I belive Right??

 

No less then 60 psi at key on,and hold above 55 for 10 min.

Codes not going to clear until you install a new cat.

 

Wouldnt it start hard if it was losing pressure though?? Starts and runs just fine everytime.