Bacon

I have a 2002 Tahoe with a 5.3 Flex that is giving me random misfires on cylinder 1 only. I replaced all plugs a couple months ago, and changed #1 again just to make sure. I put on new wires, moved the coil to cylinder 3, and did a compression check with 165psi and no leaks. I still have a misfire and can't figure out what to chase now. I thought fuel injector, but it has within spec resistance and I can hear it clicking with a scope (screwdriver to ear). Just for fun I checked the fuel pressure and it is 46-48 off-idle. Spec says 55-62....could being a little low cause only one injector to fail? Are all the others close behind or do I really have a bad injector and a likely to fail in the future pump? Im going to change the fuel filter after work and recheck the fuel pressure. Any help would be GREATLY appreciated.

Matt

01350ss

iTrader: (18)

have you ever changed the intake gasket? gm updated the gaskets from i believe green to orange (or vise versa) I have an 03 yukon with the same motor. Mine started to act wierd with low idle, idle surge, random misfire, and even stalled a couple times. I traced my problem to the intake gasket. They are cheap and very easy to replace.
Good luck, post your results please
justin

Bacon

Right after I bought the truck (almost 2 years ago) I got a lean banks 1 and 2 issue and the dealer replaced the intake gasket. If theyre trustworthy at all, they replaced it. I havent had a problem since and I wouldnt think that it would go bad again so fast...is there an easy way to check? Maybe some starting fluid around the cylinder 1 seams? Compression holds well and Im not missing any coolant, so I didnt think it was the gasket. That and the plug looked hot like it was burning lean. Any ideas on how to get the injectors out? They didnt seem to want to budge.

01350ss

iTrader: (18)

pulling the injectors is easy. just unbolt the rail, you dont even need to take the line off. once the rail is unbolted from the manifold, just lift or wiggle the rail upwards. if its stuck, some slight prying will do. Just dont go crazy with the prying and watch where you place a pry bar. You will need to release the clip on the injector. Flat blade screw driver works well here. Just dont loose the metal retainer. Once the rail and clip are off, spin, wiggle and pull the injector out.

When your ready to put the injector back in the rail, and than all the injectors back in the engine, apply a thin coat of vaseline to the o-rings of the injectors so they slide back in without tearing.

You may know all this already, but if you dont, know you dont have to ask.