My check engine light keeps coming on. I took it to get looked at and the code read misfire cylinder 3. The mechanic checked the coil, spark plug and fuel injector, took it for a ride and the vehicle is fine to drive no lost power. The dealership thinks it could be the PCM giving out the code for no reason. Is there a way to reset the PCM? Would it help with this issue?

 

Welcome to the forum\


All new member this is so important when asking for help!
Model Year, engine size, and miles. Then what and when (odo) was the last service done?

There is no "thinking" or guessing when you are Diagnostically checking the ECU/PCM. The reason that the engine check light cancels and then reappears is that there is an ongoing problem that the is not resolved. That should have been at least verified when the ECU/PCM was checked. There are a few areas that an experienced Diagnostic technician looks at. I also am wondering about their parts varying for not being at fault or other informatio0n that would have shown on any electrical ignition part using the proper method? It also takes about 2 hours to first check the normal possibilities and then to check all to you said they did??? hmm. ?
Maybe you are summarizing what was on the final work order? can you give more information what was actually on your work order service?
A Pass-through or as you would understand it a ECU/PCM FLASH with the latest program would have been I suppose one way to do things but not the correct way of checks and balances when diagnosing the cause of a DTC(check engine light and DTC in the ECU/PCM permeant files. There is also no mention of your I/M readiness which has to do with your emission s. And DTC that is related to a ignition code would place the I/M in fault. At least 1 or 2 of them?
And on and on and on... really either the shop did a less then quality check or they did not really know what they were doing?

Btw one last question did they load test your battery? And if so what was the result?

 

I had a misfire on cylinder 2. Checked the plug and coil and they were fine. Took out the injectors and had them cleaned at RC Injection on Callistos recommendation. Problem went away. The flow rate report showed cylinder 2 flow was half of what it should be.

How was the technician able to check the flow rate and spray pattern of the injector without removing the injector and putting it on a bench tester?

 

you information is not clear as to who after RC did the service determined the injector issue?

 

I was having P0302 code everyday after clearing the code.

Swapped coil put in new plug, still code P0302 everyday.

Cleaned fuel injectors, injector 2 had the worst flow rate according to data.

No P0302 code after cleaning injectors.

Cylinder misfire count on cylinder 2 went from ~275 to 350 counts a trip to 1 count a trip.

 

I did clean the intake valves, so that is another variable that cannot be ruled out. But the injector bench test data pointed to cylinder 2 injector being way lower then the rest.

 

Ok I am pretty sure we covered possible reasons? maybe go re-read you thread again?
I have posted cause and ways to do a correct service procedure to find and resolve at least a dozen or more times on this forum.

 

One test I wish would have done, is to see if off the shelf fuel injector cleaners in high concentrations could have dropped the misfire counts low enough to keep the check engine light off.

Do you think the OP could try Redline SL-1 in half a tank of gas to see if the check engine light goes off. Maybe do this a few times over several hundred miles.

 

Oh this was not your problem?? lol

sure STP or Chevron fuel injector cleaner and or octane booster with 1/2 of less tank of fuel is always a good idea.

 

You will want the fuel injector cleaner with the most amount of PEA in it.