Help with misfire

[frostbite]

Hello all, I am new to this forum and I come with a question. I have an 04 Sierra with the 5.3 and I have had issues with this misfire ever since I bought it, it has no misfires what so ever on the 2nd bank (2,4,6,8) but every cylinder in bank 1 (1,3,5,7) has a misfire present. cylinders 1 and 2 are the worst, 3 and 4 are minimum but still there. When I first purchased the truck it had a poor idle so I did a tune up (plugs and wires) with no fix so I swapped known working coils from a parts 5.3 I had sitting around and the issue still persists. The only code is for engine misfire so I don't have a lot to go on. I am hoping this is a common issue or atleast something that another member has encountered and has a solution.

Thanks ahead of time for all of your responses

 

[19trax95]

I'd check the intake gasket to start.

I sometimes let the truck idle and spray a little ether on the suspect side of the intake. If the idle speeds up or changes then you know there is a leak.

Just don't go crazy with the ether.

If there isn't a intake leak then I'd look at fuel or ignition issues.

It's not a bad idea to change plugs and wires off the bat anyway. Acdelco is best for both. You'll want the iridium plugs 41-110 is the plug number.

 

[gmac53]

check intake, egr, and pull code and see if it is the knock sensors. i just replaced my plugs gapped at .040 wires to coils knock sensors and harness injr=ector rings top and bottom intake gaket and egr gasket now she runs great like rollin off lot, the knock sensors are common to fail due too poor design tsb was put out be cause water would collect near and evetually fill sensor area with moisture/water causing failure. heres the cheapest set up i found for harness and sensors

https://www.google.com/aclk?sa=l&ai...y=2001&utm_campaign=gb_csv_br&utm_content=EEK

btw to check knock sensor without scanner. take and tap near or around sensor area at idle. if idle changes sensors are fine if no compensation is made from the forced "knock
then iits bad replace.