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Vehicle make/model = 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.

tip/donation yes
tech = JK OR MW
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!!!!!!






JK:
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.
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.