I have a nice popping sound coming from my exhaust, but only when it warms up. I replaced the upper plenum gasket, cleaned my fuel injectors, new wires, and plugs. I put everything back the way it was and now have this popping sound. Any help on what might be the cause of this would be greatly appreciated. Oh, and it didn't do it before said repairs.

 

Welcome to the forum

Pop from exhaust, a back fire, is caused by a cylinder misfiring, so the air/fuel mix is sent into the exhaust system unburned and then the next firing cylinder's HOT gases ignites it, and "pop"
Exhaust has to be warmed up for unburned mix to ignite

Check firing order on distributor then check it again, very common to reverse wires

Or could be one of the new spark plugs are misbehaving and not firing every time once warmed up, very hard to track that down
Does the pop happen only at idle or only when accelerating or only ???

 

Happens during accelerating also. Runs perfect at idle, which made me think it wasn't mixed plug wires. Might be the plugs I guess I can look at them, not sure how to tell if they're not firing right.

 

There is no way to tell if a new spark plug is misbehaving, or which one if it is

You can clean and swap in an old one, they all worked, and drive it, if no change then that one new one is OK so swap it with next new one, and just go down the line until popping stops, then last one changed was the bad new one

New Spark plug wires can also have a fault, arcing
On a dark night in a dark area open the hood and start warmed up engine
Look for arcing on the wires usually easy to see if its enough to cause misfires, REV engine as well

What this is all based on is that there was no popping before adding new parts
So best guess is that one of the new parts is causing the popping

 

Well, you were right on the plug wires. I had the 2 and 3 wires switched. But now I have a rough idle, not sure why. Idle was perfect before I corrected the plugs. So if you got any ideas on why that is going on, it would be greatly appreciated.

 

So "popping" is gone but idle is now rough, that is odd

Does it seem to run OK under load, has adequate power?
No hesitation or mis-fires under load?

Just rough idle

 

Got the idle to settle down some, still a little rough but not as bad, changed out the MAP sensor. No more knocking though after the wire swap. So thanks for that little bit of info, could've thought I put them in right to begin with. Took it out drove around and I could smell a burning metallic smell. First thought was the transmission but on further review it's the front brakes. The truck sat since like 2016 so not sure if they were bad to begin with. I did change out the back brakes because they were leakiing. Didn't even check the front ones which I should've done when I did the back ones.

 

Spec spark timing is 10deg BTDC, but some prefer 12deg BTDC for smoother running

When calipers sit for a long time they will get a ridge around the piston, so when put back into use the piston won't retract back all the way
There is no "return springs" on disc brakes, like there is on shoe/drum brakes, they clamp pads to disc with fluid pressure then stop clamping with 0 pressure
So if piston can't move freely out and then back in then pads will rub more than they should

The number of times I have mis-wired a firing order would be in the...................well alot
The number of times I would have sworn it was NOT mis-wired, would be the exact same number, lol