Misfire???

[Sinbad]

Anyone ever have issues with a misfire out of nowhere. I let the truck sit for about a month and when I came back it started to misfire. I would like to fix this myself without going to the stealership if anyone has any experience with this I would appreciate the help. It will start after about the first 15 min of driving. Like clockwork. Ive changed the plugs and still no change. It is not throwing a check engine light so im not sure whats going on. count me lost in the sauce here boys.

 

[VPRPWRD]

This stealership employee is happy to help you out, even though you don't want to pay us for the service we offer.

ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT CRANK 1. Weak or discharged battery. 1. Charge or replace battery as necessary. (Refer to 8 - ELECTRICAL/BATTERY SYSTEM - DIAGNOSIS AND TESTING). Check charging system. Refer to the appropriate Diagnostic Information for charging system diagnosis.
2. Corroded or loose battery connections. 2. Clean/tighten battery/starter connections.
3. Faulty starter or related circuits. 3. Check starting system. (Refer to 8 - ELECTRICAL/STARTING - DIAGNOSIS AND TESTING).
4. Seized accessory drive component. 4. Remove accessory drive belt and attempt to start engine. If engine cranks, repair/replace seized component.
5. Engine internal mechanical failure or hydrostatic lock. 5. (Refer to 9 - ENGINE - STANDARD PROCEDURE - HYDROSTATIC LOCKED ENGINE).
ENGINE CRANKS BUT WILL NOT START 1. No spark. 1. Check for spark. Refer to the appropriate Diagnostic Information for ignition system diagnosis.
2. No fuel. 2. Perform fuel pressure test. Refer to the appropriate Diagnostic Information for fuel system diagnosis.
3. Low or no engine compression. 3. Perform cylinder compression test. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE TEST).
ENGINE LOSS OF POWER 1. Worn or incorrect gapped spark plugs. 1. Replace spark plugs or set gap.
2. Dirt or water in fuel system. 2. Clean system and replace fuel filter.
3. Faulty fuel pump. 3. Replace fuel pump.
4. Incorrect valve timing. 4. Correct valve timing.
5. Blown cylinder head gasket(s). 5. Replace cylinder head gasket(s).
6. Low compression. 6. Test cylinder compression. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE TEST)
7. Burned, warped, or pitted valves. 7. Install new or reface valves as necessary.
8. Plugged or restricted exhaust. 8. Replace parts as necessary.
9. Faulty ignition cables. 9. Replace ignition cables as necessary.
10. Faulty coil(s). 10. Test and replace as necessary.
ENGINE STALLS OR ROUGH IDLE 1. Carbon buildup on throttle plate. 1. Remove throttle body and de-carbon.
2. Engine idle speed too low. 2. Check Idle Air Control circuit. Refer to the appropriate Diagnostic Information for IAC motor testing.
3. Worn or incorrectly gapped spark plugs. 3. Replace spark plugs or set gap.
4. Faulty or crossed ignition cables. 4. Check for correct firing order or replace ignition cables as necessary.
5. Faulty coil(s). 5. Test and replace as necessary.
6. Intake manifold vacuum leak. 6. Inspect intake manifold gasket and vacuum hoses. Replace as necessary.
ENGINE MISSES ON ACCELERATION 1. Worn or incorrectly gapped spark plugs. 1. Replace spark plugs or set gap.
2. Faulty ignition cables. 2. Replace ignition cables as necessary.
3. Dirt or water in fuel system. 3. Clean system and replace fuel filter.
4. Burned, warped, or pitted valves. 4. Install new or reface valves as necessary.
5. Faulty coil(s). 5. Test and replace as necessary.

Factory service manual for diagnosing drivability concerns.

 

[10-1=9]

This stealership employee is happy to help you out, even though you don't want to pay us for the service we offer.

ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT CRANK 1. Weak or discharged battery. 1. Charge or replace battery as necessary. (Refer to 8 - ELECTRICAL/BATTERY SYSTEM - DIAGNOSIS AND TESTING). Check charging system. Refer to the appropriate Diagnostic Information for charging system diagnosis.
2. Corroded or loose battery connections. 2. Clean/tighten battery/starter connections.
3. Faulty starter or related circuits. 3. Check starting system. (Refer to 8 - ELECTRICAL/STARTING - DIAGNOSIS AND TESTING).
4. Seized accessory drive component. 4. Remove accessory drive belt and attempt to start engine. If engine cranks, repair/replace seized component.
5. Engine internal mechanical failure or hydrostatic lock. 5. (Refer to 9 - ENGINE - STANDARD PROCEDURE - HYDROSTATIC LOCKED ENGINE).
ENGINE CRANKS BUT WILL NOT START 1. No spark. 1. Check for spark. Refer to the appropriate Diagnostic Information for ignition system diagnosis.
2. No fuel. 2. Perform fuel pressure test. Refer to the appropriate Diagnostic Information for fuel system diagnosis.
3. Low or no engine compression. 3. Perform cylinder compression test. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE TEST).
ENGINE LOSS OF POWER 1. Worn or incorrect gapped spark plugs. 1. Replace spark plugs or set gap.
2. Dirt or water in fuel system. 2. Clean system and replace fuel filter.
3. Faulty fuel pump. 3. Replace fuel pump.
4. Incorrect valve timing. 4. Correct valve timing.
5. Blown cylinder head gasket(s). 5. Replace cylinder head gasket(s).
6. Low compression. 6. Test cylinder compression. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE TEST)
7. Burned, warped, or pitted valves. 7. Install new or reface valves as necessary.
8. Plugged or restricted exhaust. 8. Replace parts as necessary.
9. Faulty ignition cables. 9. Replace ignition cables as necessary.
10. Faulty coil(s). 10. Test and replace as necessary.
ENGINE STALLS OR ROUGH IDLE 1. Carbon buildup on throttle plate. 1. Remove throttle body and de-carbon.
2. Engine idle speed too low. 2. Check Idle Air Control circuit. Refer to the appropriate Diagnostic Information for IAC motor testing.
3. Worn or incorrectly gapped spark plugs. 3. Replace spark plugs or set gap.
4. Faulty or crossed ignition cables. 4. Check for correct firing order or replace ignition cables as necessary.
5. Faulty coil(s). 5. Test and replace as necessary.
6. Intake manifold vacuum leak. 6. Inspect intake manifold gasket and vacuum hoses. Replace as necessary.
ENGINE MISSES ON ACCELERATION 1. Worn or incorrectly gapped spark plugs. 1. Replace spark plugs or set gap.
2. Faulty ignition cables. 2. Replace ignition cables as necessary.
3. Dirt or water in fuel system. 3. Clean system and replace fuel filter.
4. Burned, warped, or pitted valves. 4. Install new or reface valves as necessary.
5. Faulty coil(s). 5. Test and replace as necessary.

Factory service manual for diagnosing drivability concerns.

But what is wrong with my truck this time? If I call you could you hold the phone up to it?

I vote for #3 perform cylinder compression test.

 

[NukeGM/Ford]

diagnosis by phone, perfect idea