The plastic intake will need to be removed. The injectors or poppet valves in your case they are the same, will come as a unit. All 8 poppet valves will look like a giant spider. Here is a tsb for plugged injecotrs.
Bulletin No.: 03-06-04-030A
Date: June 24, 2004
TECHNICAL
Subject:
Multiple Driveability Symptoms Due to Clogged Fuel Injectors (Clean Injectors)
Models
Supercede:
This bulletin is being revised to update the procedure, models and model years. Please discard Corporate Bulletin Number 03-06-04-030 (Section 06 - Engine).
Condition
Some owners may comment on driveability symptoms of long or hard starts, chuggle, rough idle and light or intermittent misfire. The malfunction indicator lamp (MIL) may also illuminate.
Cause
Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.
Correction
Fuel injector restrictions, deposits, can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened.
Note: The recommended mixture amount of GM Top-Engine Cleaner has been increased from 5% used in prior procedures to 10%. This increase was implemented to improve the effectiveness of the injector cleaning procedure. Follow the cleaning procedure carefully to minimize the risk of fuel system damage. Testing has demonstrated that exceeding the 10% cleaning solution concentration does not improve the effectiveness of this procedure. GM Top-Engine Cleaner is the only injector cleaning agent approved for use with General Motors fuel system components. Other injector cleaners may cause damage to plastics, plated metals or bearings. General Motors has completed extensive laboratory testing of GM Top-Engine Cleaner, and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is followed correctly.
Important: This bulletin recommends the use of pre-measured containers of GM Top-Engine Cleaner, P/N 12346535, - U.S. USAGE ONLY. Pre-measured containers eliminate the need to measure the amount of GM Top-Engine Cleaner being added to the J 35800-A, injector cleaning tool. In Canada, use P/N 992872. It will be necessary to measure and dispense Top Engine Cleaner into the J 35800-A, injector cleaning tool.
Fretting is a term used to describe a tiny rubbing motion that occurs between two surfaces. Fretting corrosion refers to a build up of insulating, oxidized debris that forms on electrical connections due to a fretting action at the contact points. Injector vibration, engine vibration, and electrical harness movement are contributors to the fretting motion.
Depending on how large the build-up of oxide is will determine how drastic the effect will be on the injector circuit. Worst case is a total loss of continuity in the connection resulting in P0200 (Injector Circuit Fault) and P0300 (Misfire) codes being set. If the oxides create a high resistance circuit, insufficient current will be available to properly open the injector, resulting in unstable fuel delivery and ultimately a P0300 DTC. High resistance in the circuit will not necessarily set a DTC P0200. Keep in mind that a connection with fretting corrosion is unstable. Since movement causes fretting, any vibration may create a condition where the connection varies from an open circuit, to a high resistance connection, to a good connection.
Important: Unless intermittent mis-fire due to fretting corrosion is suspected when servicing 3.1 L and 3.4L engines, skip steps 1 through 4. Steps 1 through 4 may be performed at a future date when the upper intake is removed.
When servicing 2.8L, 3.5L or 4.2L engines (VINs 8, 6, S - RPOs LK5, L52, LL8) skip steps 1 through 4 unless replacing injectors.
1. Disconnect one injector electrical connector.
2. Apply a small amount, about the size of a BB, of dielectric grease, P/N 12377900 (in Canada, P/N 10953529) to the female terminal. Be sure to cover both cavities.
3. Reconnect electrical connector to injector.
4. Repeat steps 1 through 3 for all remaining injectors.
5. Using the Tech 2(R), perform an injector balance test using the procedure in the appropriate Service Manual. Use the Tech 2(R) to select each individual injector. Record the pressure drop of each injector on the repair order.
Important: When replacing injectors be sure to add dielectric grease to injector electrical connectors.
The pressure drop is greater than or equal to 20 kPa. Injectors 1 and 3 appear to be lean when compared to injectors 2, 4, 5 and 6. Clean and re-test pressure drop. If cleaning does not restore flow on injectors 1 or 3, replace the detective injector or injectors as necessary. Charge time to labor operation J5650.
Injector Cleaning Procedure
Note: GM Top-Engine Cleaner is the only injector cleaning agent recommended. DO NOT USE OTHER CLEANING AGENTS, AS THEY MAY CONTAIN METHANOL WHICH CAN DAMAGE FUEL SYSTEM COMPONENTS. Under NO circumstances should the GM Top-Engine Cleaner be added to the vehicle fuel tank, as it may damage the fuel pump and other system components.
Do not exceed a 10% cleaning solution concentration. Higher concentrations may damage fuel system components. Testing has demonstrated that exceeding the 10% cleaning solution concentration does not improve the effectiveness of this procedure.
During this procedure, you will need a total of 960 ml (32.4 oz) of cleaning solution (10% Top Engine Cleaner/90% Regular Unleaded Gasoline). That is two tanks of solution for the J 35800-A Fuel Injector Cleaner Tank. Other brands of tools may have a different capacity and would, therefore, require more or less tanks to complete the procedure. You must use all 960 ml (32.4 oz) of solution (10% Top Engine Cleaner/90% Regular Unleaded Gasoline) to insure complete injector cleaning.
Important: Vehicles with less than 100 miles (160 km) on the odometer should not have the injectors cleaned. These vehicles should have any out of specification injectors replaced.
1. For U.S. dealers, empty 2 pre-measured GM Top-Engine Cleaner containers, 24 ml (0.812 oz) each, P/N 12346535, into the J 35800-A, injector cleaning tank. For Canadian Dealers, measure and dispense 48 ml (1.62 oz) of Top-Engine Cleaner, P/N 992872, into the J 35800-A, injector cleaning tank. If you are using any other brand of tank, you will need a total of 96 ml (3.24 oz) of Top-Engine Cleaner mixed with 864 ml (29.16 oz) of regular unleaded gasoline.
2. Fill the injector cleaning tank with regular unleaded gasoline. Be sure to follow all additional instructions provided with the tool.
3. Electrically disable the vehicle fuel pump by removing the fuel pump relay and disconnecting the oil pressure switch connector, if equipped.
4. Turn the ignition to the Off position.
5. Relieve fuel pressure and disconnect the fuel feed and return lines at the fuel rail. Plug the fuel feed and return lines coming off the fuel rail with J 37287, J 42873 or J 42964 as appropriate for the fuel system.
6. Connect the J 35800-A to the vehicle fuel rail.
7. Pressurize the J 35800-A to 510 kPa (75 psi).
8. Start and idle the engine until it stalls, due to lack of fuel. This should take approximately 15-20 minutes.
9. Turn the ignition to the Off position.
10. Refill the J 35800-A injector cleaning tank per steps 1 and 2.
11. Start and idle the engine until it stalls, due to lack of fuel. This should take approximately 15-20 minutes.
12. Turn the ignition to the Off position.
13. Disconnect J 35800-A from the fuel rail.
14. Reconnect the vehicle fuel pump relay and oil pressure switch connector, if equipped.
15. Remove the J 37287, J 42873 or J 42964 and reconnect the vehicle fuel feed and return lines.
16. Start and idle the vehicle for an additional 2 minutes to ensure residual injector cleaner is flushed from the fuel rail and fuel lines.
17. Repeat Step 5 of the Injector Balance Test and record the fuel pressure drop from each injector.
18. Subtract the lowest fuel pressure drop from the highest fuel pressure drop. If the value is less than 15 kPa, no additional action is required. If the value is greater than or equal to 15 kPa, replace the injector assembly with the lowest fuel pressure drop. Follow injector replacement procedures outlined in the appropriate Service Manual Information for the vehicle. Repeat balance test to ensure that all injectors fall within 15 kPa.
19. Add one ounce (30 ml) of Fuel System Treatment, P/N 12345104 (Canada P/N 89020804), to the vehicle fuel tank for each gallon (3.78 L) of gasoline estimated to be in the fuel tank. Instruct the customer to add the remainder of the bottle of Fuel System Treatment to the vehicle fuel tank at the next fill-up.
20. Advise customer to change brands of fuel and to add GM Fuel System Treatment at every oil change. Regular use of GM Fuel System Treatment should keep the customer from having to repeat the injector cleaning procedure.
21. Road test the vehicle to verify that the customer concern has been corrected.
Edited by amedee on July 10 2006 at 6:58 PM