my 99 4.3 was running perfect no skipping missing no nothing no cel and on Friday it blew a lower intake manifold gasket, I tore it apart and replace the lower intake manifold gasket put it all back together and it runs perfect again other than a small skip/ miss but it doesn't do it all the time any thoughts on that?

new plugs right after fixing, recent cap,rotor,wires,iac,tps

 

My truck was doing this. Look under the hood at night ,check the spark plug wire for arcing. You,ll see a blue spark and may even hear it

 

If it didn't have it before, it 'most likely' is something you did/touched. Goo back over all you did....hoses tight, not cracked (a carb cleaner may help with this)..all electrical is plugged in properly (ie plug wires seated to cap tightly)..good luck...Jerry

 

Yes, agreed

 

alright. will check. and i cleaned throttlebody really good whennit was off already.
thanks i will post what i find

 

i found a bad spark plug wire havent. replaced it yet. but pretty sure thats causing the problem

 

I would bet thats it. Let us know

 

captain hook. i never have had a p1345 code until i had to change lower manifold gaskets and put the distributor back in how do i fix it
thanks

 

With the ignition off: Using a ratchet and socket on the crankshaft center bolt, manually rotate the crankshaft ONLY clockwise until the timing marks are aligned like this:



AND the rotor is within a few degrees of this:



Remove the distributor and install it so the rotor points to the #6, (or very close) on the distributor housing when the distributor is fully seated against the intake manifold. DO NOT rotate the crankshaft while the distributor is removed.

 

i did tdc and rotor is close to pointing to the 6
i would post picture but i cant get it to upload for some reason