Quote:
Originally Posted by 4thGen4.7
Hey everyone - My 04 4.7L v8 is having misfire on all cylinders, codes P300-P308. When I start it up, it will run for a few seconds until it dies. I was able to eventually start it up enough to where it would idle until I turned the key off. The idle is really, really rough though. No response to throttle (kills it), but when it revs up to 2k on start, it sounds perfect, it just gets rough when it comes back down to ~500-1k RPMs.
So, this started happening when I replaced the starter. I installed new gaskets for the lower manifold (didn't remove upper) - originally didn't swap injector o-rings and grommets, but when I ripped it apart to do it again after having issues, I used all new rubber.
One thing that did happen after I could get it to run for a bit was tons of smoke coming from passenger side cat, which has an O2 sensor I replaced about a year ago that hasn't given me any problems. It seems to have all burnt off though because there is no more smoke.
I built a DIY smoke machine and tested for vacuum leaks from the intake duct after the MAF, didn't see any leaks but there is a chance I couldn't get enough smoke past the throttle body flange, i'll be testing that again.
I cleaned MAF and throttle body.
I replaced all spark plugs. Nothing too bad with the old ones other than one with a lot of oil on it (I have leaky valve cover gaskets, going to swap those this weekend too)
I have a fuel pressure gauge but I either 1. don't know what tf I'm doing or 2. it is faulty, because I'm getting 0 pressure from the inline, despite hearing the pump come on and getting some fuel delivery. I want to spend more time on this this weekend.
One thing that could be cause for concern, because I lubed up the injector o rings and grommets, I have injectors that are easy to rotate in their spots, but no leaky injectors. How tight are these fuel rails supposed to be? No torque spec in Chilton manual.
I have noticed that when I crack open a banjo bolt on the crossover, or when I swapped the fuel pressure regulator that, even though fuel comes out, it doesn't seem to be as pressurized as it could be, given the volume that comes out.
I replaced PVC and PVC hose.
I'm really leaning towards it being a fuel delivery problem, but what are the chances that I could have dead fuel parts right when I fix a starter?
THANKS IN ADVANCE
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If it ran fine prior to replacing the starter, then chances are parts weren't installed correctly or something got damaged in the process. P0308 is a misfire for cylinder 8 which is the cylinder closest to the firewall on the P/S bank. I'd start there and then inspect the rest of your spark plugs. Make sure that the vacuum line leading to the fuel pressure regulator is on securely and free of cracks. Also, verify that you installed the intake manifold gaskets in the proper orientation - the white tab on the gaskets should be on the top and facing toward the intake manifold.
First thing to do is to throw the Chilton's manual in the garbage and download the Factory Service Manual below. You will want the 2003 manual for your 2004 MY.
The fuel injectors should move fairly easily back in forth on the fuel rails but you can easily damage the o-rings by rotating them. The torque spec for the fuel rail nuts are 16 ft/lbs. You should also replace the banjo crush washers anytime you remove a banjo bolt.
Service Manual Download Links.
