I have a 2002 escalade. I ahve a po307 misfire. I was told it was fuel pump. Replace fuel pump, replaced plugs and wires. Plug is always dark and wet. I switched coils and problem stayed with number 7. I also listened to injector with stethescope and hear if clicking. I also tested wiring harness to injector. I ohmed injector s and coils and they are fine. I am running mout of options. help!
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Re: po 307 misfire on #7
Just because injector test ok electricly that doesnt mean its working right if the tip is plugged instead of sprayying a fine ignitable mist of gas it just drips out if this happens the gas wont ignite and you get a wet plug. you can switch injectors from one cylinder to anther or you can just replace #7 let me know how you make out with this
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The P0302 code means that the cylinder 2 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 2. If the problem persist more tests needs to be done. PO307 is the same thing except number 7 cylinder.
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation
When a misfire occurs, engine speed will fluctuate. If the engine speed
fluctuates enough to cause the crankshaft position (CKP) sensor (POS)
signal to vary, Powertrain Control Module (PCM) or Electronic Control Module (ECM) can determine that a misfire is occurring.
Causes: - Improper spark plug - Insufficient compression - Incorrect fuel pressure - The injector circuit is open or shorted - Fuel injectors may be faulty - Intake air leak - The ignition signal circuit is open or shorted
Causes: A code P0307 may mean that one or more of the following has happened: * Faulty spark plug or wire * Faulty coil (pack) * Faulty oxygen sensor(s) * Faulty fuel injector * Burned exhaust valve * Faulty catalytic converter(s) * Running out of fuel * Poor compression * Defective computer
Possible Solutions: If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Hey; Code 307 is a code for misfire on cylinder #7. It could be caused by bad spark plug, ignition module. If engine has a miss then I would replace the spark plug first. If that don't fix then it will require further diagnosis with a scan tool. Code PO410 is for the secondary air injection system. Make sure the vacuum hoses going to the valves on the front and rear cylinder banks are connected and the hose(s) not damaged. Also make sure the solenoid is connected both electrical and vaccum' Maybe this will help