MILD THUNDER

iTrader: (3)

Black Baja is right. The distributor "Cam position offset" I think its called, needs to be set/checked via a scan tool. Its not like the old stuff where you can just throw a timing light on the balancer.

If the Distributor is like the one in my Vortec 454, they are plastic housings, and a throw away item. I replaced mine at 89k miles, the gear was worn. I replaced it with an aftermarket with a billet housing. I've heard of guys complaining about rough idle with certain aftermarket caps too. Some guys claim the Delphi cap is the only cap to use on these engines.

Does it have a MAF sensor?

boatnt

iTrader: (1)

some things for you to check,,
1st, remove the EGR and see if there is an carbon holding the EGR pintle open,
2nd,remove the Intake Manifold tuning valve and look inside the intake plenum for and puddles of fuel or any spots where it might look really clean (like fuel washing it clean) if you find signs of fuel remove the upper plenum and cycle the key so you get fuel pressure and check the fuel feed and return lines for leaks.
both very common issues

other than that you will have to check fuel pressure,scan data,read o2 data and remove the air intake temp sensor and spray some carb clean while engine is running and see if the o2 reading goes high (lean command because now it sees a rich condition)
if all checks out good and you still think its a bad o2 you can unplug the pre o2s (fronts) it than will read a fix 02 reading of 450mv and should run better but will tricker the check engine light on,

the ignition on that engine is pretty good,no real issues ,while its running take a spray bottle and lightly spray water on coil see if it starts arcing,

other than that the only other thing you could check is the crank sensor harness,it sometimes melts on the right exhaust manifold,

also dont over look fuel,,put a sample in a clear jar and let it sit for about 10 minutes and see what it looks like and if it separates,

FIXX

iTrader: (2)

if any of this were the case it would set a p1345 ''camshaft to crankshaft correlation code''

Black Baja

iTrader: (2)

Not true

FIXX

iTrader: (2)

Im not here to argue with you,,i have done many distributor reset's that someone had just done lower intake gaskets on and everyone had a p1345 code...i weht in with a tech 2 to see where the timing was at and had to redrop the distributor then set the timing and the code went away..

Black Baja

iTrader: (2)

Yes I've done the same thing many times fixing someone's screw up. But, whenever I've had them come in with a run problem and misfiring due to bad distributor or drive gear on the cam guess what? No correlation code. Ok now doesn't make sense at all. Only time I've seen it throw the correlation code is when it was already messed with. Otherwise no code. Only thing I can think of is because it is setting misfire codes that its not going into the part of the PCM's readiness for the correlation code. I've seen this issue atleast 20 times more so on the 4.3 with balance shaft but have seen on 5.7 and 7.4

FIXX

iTrader: (2)

yes i agree with you about the 1345 and cam gear not setting a code,,only when someone mess's with it..

check this out,,i got in a 2000 astro that kinda kicked my ass,,had a po401 403 which is the egr..it also had a po301 cyl 1 misfire..heres the kicjer,,fuel pressure at koeo 60 and koer 55 normal rite,,well it was blowing smoke rings out the tail with white smoke and a vary strong gas smell VARY STRONG.. was not the fp regulator or a cracked hose on the injector spyder..i did a compression check after the cylinder dryed out,,130 psi,,started it with a new plug still major smoke,,did another compression ck on cyl 1 now 90 psi,,cleared snapon compression gauge,,now 30 psi..i was like wtf???????? so i put the plug back in cyl 1 started it pulled wire off cyl1 and 3 no running change..pulled plugs in cyl 1 and 3 and put my leak down checker set on number one and ! tdc both rockers closed...i got air in 2 cylinders...blown head gasket..all the fuel is flooding cylinder #1...200 k going to scrap yard..