Hello all, new member first post. Signed up and have been searching, reading, and watching videos but I still don't know what to think about this. Car is currently sitting at a shop parking lot and they gave me a price for them to get to and open the valve cover but they can't say that's where the problem is or if they will have an answer to the problem. If they need to go further than it's gonna be more money to chase it down. All they know is CEL is pointing to #4.
Just looking for insight and suggestions, what direction the diagnosis should take, where to start or any prelim tests before start opening stuff up? I'm all over the place on what it could be and every video I see I think something else. Trying to limit expenses on just getting an answer only to find out I spent hundreds of dollars only to find out it's not repairable and have to buy an engine on top of what I'm out in labor. I'm sure if it's not found right away the labor could end up costing at least 1/2 of the price of a motor .
Rocker arm/bolt, spring, push rod, lifter, cam, hinge pin & piston damage, lower end bearing or rod are all the things that I've seen as possible problems to cause the noise. Anyone with insight, experience, or suggestions on what diagnostic route to go or how to narrow it down? I've thought about doing it myself as I've watching the LIM/lifter replacement video but if it's not something in the valve cover then I would be lost beyond that.
2004 Grand prix GTP 3800 series 3 L32 and I'm shifting through P,R,N,D is why the sound is changing.
Scott MI
