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- Chevrolet Silverado GMT900 How does AFM Work
Step by step instructions for do-it-yourself repairs.
2008 5.3l AFM "Blown" Lifters & Camshaft $$$$
No, that would make no sense...my MPG has dropped slightly with the Range AFM disable. It's not horrible typically about 2mpg overall... my highway was near 20-21 in ideal conditions, now it's 17-19 range... city you loose about a 1 MPG...
Hello, I have a 08 Silverado with a severe miss at high speeds. I am very anxiously trying to get the problem solved and hoping that it is nothing transmission related. I am new to the forum, so could anyone give me any advice or point me in the right direction? The truck is throwing an occasional p1174 code as well as the pre cat sensor stuck lean code. I have never had any trouble with a miss, and after driving approximately 150 miles today it suddenly began to miss. Any help would be appreciated.
Hello, I have a 08 Silverado with a severe miss at high speeds. I am very anxiously trying to get the problem solved and hoping that it is nothing transmission related. I am new to the forum, so could anyone give me any advice or point me in the right direction? The truck is throwing an occasional p1174 code as well as the pre cat sensor stuck lean code. I have never had any trouble with a miss, and after driving approximately 150 miles today it suddenly began to miss. Any help would be appreciated.
That code is for a fuel trim balance.
The Fuel Trim Cylinder Balance diagnostic detects a rich or a lean cylinder-to-cylinder air/fuel ratio imbalance. The diagnostic monitors the pre-catalyst heated oxygen sensor (HO2S) signal's frequency and amplitude characteristics by calculating an accumulated voltage over a predetermined sample period. An imbalance is indicated when multiple samples of the accumulated voltage are consistently higher than the desired value.
With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 19-42 kPa. <table border="0"><tbody><tr><td align="top" valign="top">⇒</td><td align="top" valign="top">If the MAP sensor parameter is not between 19-42 kPa, refer to DTC P0106 .</td></tr></tbody></table>
Inspect the air induction system for modified, damaged, leaking, or restricted components.
Inspect the crankcase ventilation system for improper operation.
Inspect the vacuum hoses for splits, kinks, and improper connections.
Inspect for vacuum leaks at the intake manifold, the throttle body, and the injector O-rings.
Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. .
Test the fuel injectors for improper operation. .
Test for fuel contamination
Test for excessive fuel in the crankcase due to leaking injectors.
Test the ignition system for improper operation.
Test the engine for any mechanical conditions such as sticking valves, lifters, etc., which could alter the flow into the combustion chamber.
How many miles do you have? if you are near or past 100k, then plugs and wires are a very good place to start, also consider a few bottles of fuel injector cleaner for a couple of fill ups... I have had good results with Techron and BG 44K products...
I have 135,000 miles. Plugs and wires would not be a bad idea for sure. I did just run a full tank of Lucas fuel treatment through it and on the way home from a long drive still on the tank with the treatment I ran really close to out of gas. I stopped at a near gas station, filled up and about 40 miles later started missing out of no where. Could there be something to me running low on gas? Possibly fuel pump? I'm beginning to think it may be an injector problem.







