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THat also means to check the wire and the connection to the coil and plug. If either end wasn't securely clicked in place, that might foul the plug. If the coil is good and the wire is good, then something else fouled the plug and the something else is not an easy quick fix unless a rocker took a dump and that's not so bad.
Update for the misfire P0300 (Misfire Code) and the P050D (Rough Idle Cold Start): fouled spark plug. That's it.
The technician tested to make sure the spark plug was getting ignition. It was. He then replaced the spark plug. We started it up with the new spark plug, and saw no more misfire codes. The technician then sent me on a test drive ("blow the carbon out of it"). On the test drive I sensed a little sputtering only at the very beginning of the drive but about a mile later the engine was running smoothly, as it normally does. Got back to the dealership after about 20 miles, hooked up the diagnostic tool and no more codes of any kind, and certainly no more misfires (as you can see below).
The technician and service manager were in agreement that I'm not driving the vehicle like the performance vehicle that it is:
driving around town letting the automatic transmission up shift into higher gears, dropping the RPM's
not driving it for long enough time frames
not driving it often enough
All the above resulted in cylinder 8's spark plug getting fouled up pretty good. Obviously I was the cause of the CEL and codes. It was not any fault of the car or GM. Just me and my driving habits (that are soon to change).
Any body want to help me drive this thing more often?
For anyone wanting to remove spark plugs (or spark plug wires) on the right side of the engine toward the rear of the engine you will have better clearance (more room) if you first loosen the engine coolant reservoir. If the engine coolant reservoir is not moved, accessing the spark plugs (and/or spark plug wires) near cylinder 8 will be very difficult, if not impossible. Even with the engine coolant reservoir moved over the space to work within is very tight.
For anyone wanting to remove spark plugs (or spark plug wires) on the right side of the engine toward the rear of the engine you will have better clearance (more room) if you first loosen the engine coolant reservoir. If the engine coolant reservoir is not moved, accessing the spark plugs (and/or spark plug wires) near cylinder 8 will be very difficult, if not impossible. Even with the engine coolant reservoir moved over the space to work within is very tight.
Jaylars, as you can see in the image above (I learned that you can not paste/upload videos directly into the thread) on a cold start up my car's PSI is right around 35 PSI. And if I remember correctly, that's pretty close to what you guys were discussing, correct?
I have a 2018 Grand Sport (all stock). What cars (stingray, grand sport, z06, etc.) do you guys have?
Does anyone have a theory or an explanation why my car's oil pressure would have been higher than normal (during the time when cylinder 8 was misfiring due to a fowled up spark plug) and now normal?
Does anyone have a theory or an explanation why my car's oil pressure would have been higher than normal (during the time when cylinder 8 was misfiring due to a fowled up spark plug) and now normal?
After reading the message from Jaylars, I sent the following email to my GM dealership's service manager:
"Someone on the Corvette Forum looked at the images below and inferred that the oil pressure was high. Stating that his is about 27, whereas mine is just above 50. Is my fellow Corvette Forum member correct? Is my oil pressure (upon startup) high? Something else to look at next week?"
This was his response:
"Nope I assure you cold start oil pressure you would expect to see 40 to 50 psi on a healthy new engine. As the engine warms up the oil will thin and the pressure at idle will drop. If you were seeing pressure in the 25 psi range on a cold start that may present a problem with low oil pressure after the engine heats up. In other words your oil pressure indicates a very healthy engine and no reason for concern."
I share this with the CF, not to start an argument about correct PSI (because I am not an expert on motors), but instead to share a GM service manager's opinion (and reduce one's subsequent concern level) that if your relatively young and all stock LT1 motor has an oil pressure PSI reading that looks like mine upon startup, your motor might be okay.
Jaylars, does your oil pressure go high (like mine) at startup and then come down as the motor warms up? Let us know your experience. Thanks.
I do a lot of idling and low speed driving with my garage queen moving it outside I know that that’s not good in the long run. So every now and then I do an Italian tune up and boom the car runs better.
05-16-2019, 02:53 PM
