Miss at idle only

[Ponyman460]

I have been having a miss at idle since I put the motor back in the truck.

Background: completely rebuilt long block with all new gaskets. Before I pulled it, there was no miss, and now there is.

It is giving me cyl 1 missfire codes, and Both Banks 1 AND 2 LEAN.

Any help that I can get will be a HUGE help.

I have tried the starting fluid sprayed near the intake trick to see if maybe I have a gasket leak....nothing

I replaced the plug wires when the motor back in.

what are you guys thinking? Maf? O2's? leak of a gasket somewhere?

TIA!

 

[Turdle]

Try this little redneck trick-

swap the coil packs with each other-make sure the firing order is good-

then, swap the #1 #2 spark plug wire-

if the code changes to a #2 misfire, you have a bad wire
if it changes to another cylinder it is the coil pack.

If there is no change-it could be a bad plug, or internal issues.


I'd get a vacuum gauge-let's check the vacuum

 

[Ponyman460]

Try this little redneck trick-

swap the coil packs with each other-make sure the firing order is good-

then, swap the #1 #2 spark plug wire-

if the code changes to a #2 misfire, you have a bad wire
if it changes to another cylinder it is the coil pack.

If there is no change-it could be a bad plug, or internal issues.


I'd get a vacuum gauge-let's check the vacuum

nice will try that this weekend.

please dont say internal issues though :roll: I dont think I could handle another motor swap....what a pain in the ass!

 

[Ponyman460]

Changed all 8 plugs AND wires again! Found a CRACK in my 1" intake spacer....removed it and put it back to stock....STILL MISSES!

I dont know what to do at this point shy of a compression test and leak down... wish me luck