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Big Problem

15K views 24 replies 8 participants last post by  Blaqowt 
#1 ·
I am having a problem with my TB. Today while driving down the highway my check engine light came on (solid). When I got to my offramp and slowed down I noticed that the engine was sputtering. As I was rolling 2-3MPH the engine was idling and the car was jerking a bit with each sputter of the engine. When I put it in neutral the engine was doing the same thing, seemed like misfiring or something. It's still doing it, the only difference is when i step on the gas the CEL starts blinking. When I start coasting it goes back to being solid.

The truck is covered under the B2B, but I need my vehicle for work so i would rather not bring it to the dealer to sit there for days if I could fix it myself.


Anyone have any advice? Has anyone had this problem? Could it be a bad spark plug or something simple?
 
#2 ·
New to TB said:
I am having a problem with my TB. Today while driving down the highway my check engine light came on (solid). When I got to my offramp and slowed down I noticed that the engine was sputtering. As I was rolling 2-3MPH the engine was idling and the car was jerking a bit with each sputter of the engine. When I put it in neutral the engine was doing the same thing, seemed like misfiring or something. It's still doing it, the only difference is when i step on the gas the CEL starts blinking. When I start coasting it goes back to being solid.

The truck is covered under the B2B, but I need my vehicle for work so i would rather not bring it to the dealer to sit there for days if I could fix it myself.


Anyone have any advice? Has anyone had this problem? Could it be a bad spark plug or something simple?
I would carry to the dealer and request a replacement while it is in the shop.
 
#9 ·
So I went there and found code P0301 which is a misfire in cylinder 1.

Anyone know which cylinder is "1" and if it's hard to get to? I figure I'll check the wires and pull out the spark plug to check the electrode. Any other ideas are very much appreciated.
 
#11 · (Edited)
tblazed said:
I6 is the one at the front, V8 is first plug in front on driver's side.
Thanks!

I have the I6.

EDIT:
I pulled off that airbox and took off the coilpack of the cylinder closest to me, the spark plug seemed to be ok. I don't know what else to check for so I put it back together, I'll have to miss some work on Monday to take it to the dealer.

If anyone has any ideas that I can check for tomorrow please let me know.
 
#12 ·
Anyone know how much a coilpack costs from the dealer (or if I could get it from anywhere else)?

I am going to put my Father's coilpack into cylinder 1 tomorrow and see if it stops misfiring. If it;s the coilpack, and if purchasing a coilpack is cheaper than the loss of money from missing work, I'll just buy one.
 
#14 ·
h0tr0d said:
what kind of work do you do that buying the parts i cheaper than missing work?
I'm an electrician.
A coilpack for my older VW cost $75, I assume a GM part would be a little cheaper, maybe $50 or so. I'd assume most people who own TB's make more than that for a day's work, plus it's not good missing work in my trade.
 
#15 ·
New to TB said:
Anyway for me to tell for sure?
I guessed it was the coil because the same thing happened to me with my Audi a few years ago. I'm not sure how you would check it. Check for the obvious things also such as loose or damaged spark plug wire. Since the I6 has been around for awhile, the coil should be readily available. I have no idea on how much. I bet it will be a lot cheaper than the Audi though. Its coil package was around $600 and I was glad it was under warranty. It also caused the plug wires and plugs to foul. I dumped that car the following week.
 
#16 ·
Dave said:
I guessed it was the coil because the same thing happened to me with my Audi a few years ago. I'm not sure how you would check it. Check for the obvious things also such as loose or damaged spark plug wire. Since the I6 has been around for awhile, the coil should be readily available. I have no idea on how much. I bet it will be a lot cheaper than the Audi though. Its coil package was around $600 and I was glad it was under warranty. It also caused the plug wires and plugs to foul. I dumped that car the following week.
Wow, now that's a lot of money! Good thing it was covered under warranty.

Newer VW's and Audis have a coil system similar to the Trailblazer, there is a separate coil for each cylinder, they are located on the head right above each spark plug.

These coilpacks were known to go bad on some VWs and Audis, they were covered under warranty but only after they failed (and put your car into limp mode) so people would buy one to keep as a spare since it was such a common problem. I believe they cost around $75, so I would assume a GM would be ever cheaper.

I wish I could find it at an online parts vendor, but all attempts failed.
 
#17 ·
New to TB,
Maybe this will aid in your troubleshooting.

Document ID# 1524437
2005 Chevrolet TrailBlazer - 4WD


--------------------------------------------------------------------------------

DTC P0301-P0306
System Description
The powertrain control module (PCM) uses information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the PCM is able to detect individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.

DTC Descriptors
This diagnostic procedure supports the following DTCs:

DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
DTC P0305 Cylinder 5 Misfire Detected
DTC P0306 Cylinder 6 Misfire Detected
Conditions for Running the DTC
DTCs P0013, P0014, P0016, P0105, P0106, P0107, P0108, P0117, P0118, P0120, P0122, P0123, P0125, P0128, P0218, P0220, P0315, P0336, P0340, P0341, P0502, P0503, P1345, P2125, P2135 are not set.
The engine speed is between 450-5,000 RPM.
The ignition voltage is between 10-18 volts.
The engine coolant temperature (ECT) is between -7 and +130°C (+19 and +266°F).
The fuel level is more than 10 percent.
The throttle angle is steady within 1 percent.
The antilock brake system (ABS) is not active.
The transmission is not changing gears.
The A/C clutch is not changing states.
The PCM is not in fuel shut-off or decel fuel cut-off mode.
The PCM is not receiving a rough road signal.
DTC P0301, P0302, P0303, P0304, P0305, P0306 run continuously when the above conditions are met.
Conditions for Setting the DTC
The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards.

Diagnostic Aids
You must perform the CKP system variation learn procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure .

Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Test Description
The number below refers to the step number on the diagnostic table.

If the actual CKP variation values are not within the learned values, the misfire counters may increment.

Step
Action
Values
Yes
No

1
Did you perform the Diagnostic System Check - Vehicle?
--
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
Start the engine.
Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records.
Monitor all of the Misfire counters with the scan tool.
Are any of the Misfire current counters incrementing?
--
Go to Step 3
Go to Intermittent Conditions

3
Are any other DTCs set?
--
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information
Go to Step 4

4
Can any abnormal engine noise be heard?
--
Go to Symptoms - Engine Mechanical in Engine Mechanical - 4.2L
Go to Step 5

5
Turn OFF the ignition.
Remove the fuel pump relay. Refer to Relay Replacement in Wiring Systems.
Remove the ignition coil for the affected cylinder, keeping the ignition connected to the harness connector. Refer to Ignition Coil(s) Replacement .

Important
Not grounding the ignition coil may cause an erratic spark.


Connect a jumper wire between the ignition coil and a good ground.
Install the J 26792 Spark Tester on the ignition coil and a good ground.
Crank the engine.
Does the spark tester spark?
--
Go to Step 7
Go to Step 6

6
Inspect the affected cylinder spark plug boot for a missing or damaged ignition coil spring.

Did you find and correct the condition?
--
Go to Step 15
Go to Electronic Ignition (EI) System Diagnosis

7
Remove the spark plug from the cylinder that indicated a misfire. Refer to Spark Plug Replacement .
Inspect the spark plug. Refer to Spark Plug Inspection .
Does the spark plug appear to be OK?
--
Go to Step 8
Go to Step 9

8
Exchange the suspected spark plug with another cylinder that is operating properly. Refer to Spark Plug Replacement .
Operate the vehicle under the same conditions that the misfire occurred.
Did the misfire move with the spark plug?
--
Go to Step 14
Go to Step 12

9
Is the spark plug oil or coolant fouled?
--
Go to Symptoms - Engine Mechanical in Engine Mechanical- 4.2L
Go to Step 10

10
Is the spark plug gas fouled?
--
Go to Step 12
Go to Step 11

11
Did the spark plug show any signs of being cracked, worn, or improperly gapped?
--
Go to Step 13
Go to Step 12

12
Perform the fuel injector coil test. Refer to Fuel Injector Coil Test .

Did you find and correct the condition?
--
Go to Step 15
Go to Symptoms - Engine Mechanical in Engine Mechanical- 4.2L

13
Replace or gap the spark plug. Refer to Spark Plug Replacement .

Did you complete the action?
--
Go to Step 15
--

14
Replace the faulty spark plug. Refer to Spark Plug Replacement .

Did you complete the replacement?
--
Go to Step 15
--

15
Was the customer concern the malfunction indicator lamp (MIL) flashing?
--
Go to Step 16
Go to Step 17

16
Operate the vehicle at the specified value for 4 minutes.
Operate the vehicle within the Conditions for Running the DTC P0420, as specified in the supporting text. Refer to DTC P0420 .
Does the DTC run and pass?
2,500 RPM
Go to Step 17
Go to DTC P0420

17
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 2
Go to Step 18

18
Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information
System OK



--------------------------------------------------------------------------------
Document ID# 1524437
2005 Chevrolet TrailBlazer - 4WD

I never did the procedure before but I think it might give you an idea on what to look for.

Dave
 
#20 ·
h0tr0d said:
thats what i thought. id drop mine off in a minute before i spent my hard earned buck on it while under warranty. good luck with it.
Even if it meant you would lose money?? :confused:

As for the problem, it was an injector. They had it fix by the end of the day so a loaner car wasn't offered (so it worked out better that I found a ride to work). They replaced a second injector that hadn't failed yet but looked like it might soon. I'm glad to have this feeling of reliability :rolleyes:
 
#22 ·
zamar said:
Glad you worked something out. FWIF Most dealears have a night drop off so you can leave it anytime after work. Then you just have to bum a ride and not lose time at work.
Yeah, most dealers other than the one I go to :D They actually lock the gate, and since they're on the highway you can't park anywhere so off hours browsing is impossible too.

That's just my luck, tho. Picking a dealer that doesn't allow night drop off :duh: :mad: :laugh:
 
#23 ·
New to TB said:
Even if it meant you would lose money?? :confused:

As for the problem, it was an injector. They had it fix by the end of the day so a loaner car wasn't offered (so it worked out better that I found a ride to work). They replaced a second injector that hadn't failed yet but looked like it might soon. I'm glad to have this feeling of reliability :rolleyes:

i never said lose. glad to hear it was only the injector and you got it fixed.
 
#24 ·
h0tr0d said:
i never said lose. glad to hear it was only the injector and you got it fixed.
That's what I explained earlier. If not for a very freak occurance of a friend going in the same direction that day, I would have had to miss time at work. If it had been the coilpack as it was when my last car started misfiring, it would have been in my best interest to just buy a new one, I would have lost money by bringing it to the dealer and having them do it. My point being it would have been wiser for me to spend my hard earned buck on it even while under warranty.

Now it's all said and done, hopefully they found all the faulty injectors so I don't have this problem again.
 
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