2004 Chevy Trailblazer Code P0172 P0016 P0017

Question:
Symptoms, Engine runs very rough with very little power to go up small hills on highway. Trans was serviced because it was time and while it was in shop I just had it done. After the new plugs were installed it runs not much better. I am stationed in Germany with the military and it is hard to find qualified mechanics to work on American vehicles. I found your web site through yahoo and I am glad you have such a site!

2004 Chevy Trailblazer 4.2 Lt 6 cyl. Service engine soon light is on DTC P0172 Fuel Trim System Rich. Repairs = Serviced transmission, changed fuel filter, air filter and spark plugs.


 

Answer:
Many things can cause p0172-rich condition. There is a computer re-programming available to correct this code, but not usually a running problem with the engine.

Things that can cause this are excessive high fuel pressure, a stuck open injector (s) caused by contaminated fuel, poor fuel economy, vacuum leaks, a leaking fuel pressure regulator, or just a faulty oxygen sensor.

If running so bad, there should also be a history in the computer for which cylinders are misfiring. A live data stream through a scanner would reveal that. This could give indication as to which cylinder (s) have a problem. I Would suggest having fuel pressure checked, should be about 50psi. Pull the vacuum hose off the fuel pressure regulator to look for signs of fuel in the vacuum hose.


Question:
2006 Chevy Trialblazer. I've had the water pump and thermostat replaced and oil changed but it misses a little bit and shut down on me but then runned just fine.

Answer:
A missfire on the 4.2l straight six engine is most likely caused by a bad ignition coil or worn spark plug. I would suggest doing a full tune up first. Stalling could be caused by carbon buildup in the throttle blade and bore but there are many other things that can cause that. I would suggest a scan of computer codes to see if there is anything related to it stalling out.

REPLY:
I had the codes scanned and got these. P0014 & P0017 are the codes.

Answer:
OK. The P0016 is a problem in the Cam shaft position sensor and P0017 is cam and crankshaft position correlation. Your most likely cause is a failed or pluggd camshaft actuator solenoid. The solenoid fails or the screen inside gets plugged. This will cause the P0016 and P0017 codes as the relation to the cam and crank positions reading do not correlate. This sensor is quite easy to replace.

The next common cause is a failed camshaft position sensor. It is located on the front passenger side of the engine.

The next common cause is the actual cam actuator has failed or the the timing chain has stretched. Either one of these is a much bigger repair. With either repair, a relearn of the cam and crank poisitions must be done with a computer scan tool. see these links for more information...


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