I've done a bunch of searches, couldn't really find anything specific to the issues I'm having, so here's a post. Apologies if there is already a thread on this, though!

Also, go easy on me, I'm fairly new to doing my own repairs and work.

So, my truck is a '95 XL 5.0 4x4 truck with 77,000~ miles. I'm driving it across the country in a few weeks, so I decided to give it a tune up.
I got an MSD Streetfire coil, the Ford Racing 9mm silicone wires, Motorcraft ASF42C, and a Taylor 918233 Distributor cap and rotor.

I believe I gapped the plugs to roughly 0.56-0.58. (on the gap tool, the far edge of the electrode stops AT the .60 mark, I'm new to gapping plugs, so correct me if I'm wrong?) (the original ones that came out were gapped to 0.40,), and seemingly routed the plug wires correctly. (I followed the under hood diagram, and used those plastic $15 ford racing separators)

I got an intermittent CEL and 122, 123, AND 124 codes, as well as I believe 565, and some wonky shifting.

I went back to the original coil, the shifting issue seems to be all but gone, but the CEL persists.

(also of note, I broke the red hose to the vacuum reservoir and repaired it with a length of silicone hose, CEL is still there)

Any ideas? Did I gap the plugs wrong?

(another note, the truck has had an exhaust leak since I bought it, but the CEL thing is mostly new)

 

i am not sure how you are gapping your plugs, but the correct gap (according to haynes) is .044". if you have an under hood sticker that says different, you may want to go with that. (i am assuming that you have left out the "0" and that you do not have a half inch spark plug gap). codes 122, 123, and 124 are related to throttle position sensor. inspect the wiring and connector for integrity. 565 is related to canister purge circuit, so again, check the integrity of the wiring and connector.

 

According to underhood it's 0.052 to 0.056, apparently the Haynes manual is wrong in that case.

I'll check the tps. Throttle response is fine now. The aftermarket coil couldn't have messed up the tps, could it? As far as I can tell the red plastic hose going to the vacuum reservoir was the only one broken.