chevy4ever
09-16-2005, 01:38 AM
Im having problems with my silverado single cab v6 vortek 4.3. About a year ago when i got the truck.. i was getting 17/18 in city.. and like 20/22 on freeway.. Now a year later.. im getting like 10/12 in city and like 15 or so on freeway.. WHAT IS GOING ON... i have replaced fuel filter.. i have cleaned the KNN air filter.. i have kept up with oil changed.. i have used fuel injector cleaners.. used octane boosters once in a blew moon.. that stuff from lucas most of the time. The only thing i havnt done is changed plugs. A friend of mine thinks its a vacum leak.. but nothing visable.. and i cant hear anything.. Any ideas guys.? if not can you suggest a site with a forum for newer trucks?? thanks in advance..
Matt
Joe67
09-16-2005, 08:08 AM
How many miles on the plugs? I know they are rated to 100K, but that is BS, mine were toast at 80K.
When you cleaned the K&N filter, were you careful not to over oil it? Sometimes people do over oil it and the oil gets on the MAF sensor and throws things off. They end up cleaning the MAF (very carefully...).
Have you made any other changes like tire size, etc?
67ChevyRedneck
10-04-2005, 11:52 AM
This thread is a little old, but you may want to try GM-Trucks.com if your still having the problem. They have helped me with my truck. Could be anything from plugs to a bad sensor, possibly an O2? A dirty MAF will do that too. Is your message center giving out any malfuntion reading?
_Dick_
10-09-2005, 06:47 AM
You might try for help here
http://forums.s-series.org/index.php
good luck most help i can give you
72CSTC5
10-13-2005, 11:35 PM
Have you checked your distributor cap and make sure there is not any moisture in there. There is a service bulletin on these trucks where the a/c line against the firewall is too close to the cap and causes it to sweat inside the cap. Check that out.
They actually recalled most of em for the distributor cap now, might check into that, you get a free cap n rotor and they put a sleeve over the ac.
Without being able to play with it I cant say for sure why the MPG problems, but i would get a fuel pressure gauge on it and make sure the fuel pressure regulator isn't leaking, or the injectors aren't leaking...