Models affected:

2000-2009 All GM Passenger Cars with Gasoline Engines

2000-2009 All GM Light Duty Trucks with Gasoline Engines

Condition/Concern:

Crank no start when cold. The engine may crank over very fast, as if
there is low/no compression. It may also run rough for up to 5 minutes
after starting the engine and may exhibit a P0300 DTC too. This may be
caused by sticking valves due to fuel contamination. When the engine is
cold, the compression on multiple cylinders may be at 0 psi.

The engine also may pop through the intake or exhaust while cranking and
the spark plugs may be fuel fouled when inspected. Some engines may
also experience valve damage or cam followers that are out of position
as a result of this.

This condition will normally occur in specific areas of the country for a
period of time and then it will no longer occur after the suspect fuel
source has been consumed in that part of the country.

Recommendation/Instructions:

If the diagnosis indicates a compression loss due to sticking valves,
the following information may helpful to your installer customers: If there is no sign of valve damage
or cam followers that are out of place, perform the following 
procedure to free up sticking valves and to prevent the valves from
sticking again.

If valve damage is present or if there are cam followers that are out of
place, perform engine mechanical repairs as  necessary to correct the
concern and then perform the procedure below to prevent the valves from
sticking again.

1. Clean the fuel system by following the applicable "Fuel System
Cleaning" procedure outlined in service information or appropriate
service manual.

2. Add fuel injector cleaner "GM Fuel System Treatment PLUS," p/n
88861011 (for U.S. ACDelco®, use 88861013) (in Canada, 88861012)

3. Refill the fuel tank using fuel from a high volume, high quality filling station.

4. Clean the induction system using GM Top Engine Cleaner. Follow the
directions on the can but DO NOT force the engine to stall since forcing
the engine to stall with liquid Top Engine Cleaner could cause the
engine to hydro-lock.

5. Advise the customer to change fuel filling stations. They should use
fuel from only high volume, high quality filling stations or they should
use a Top Tier Detergent Gasoline if available.  

Note: If the condition is not eliminated chemically, it may be necessary to remove the valves to manually clean the stems.

Please follow this diagnostic or repair process thoroughly and complete
each step. If the condition exhibited is resolved without completing
every step, the remaining steps do not need to be performed.

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.