So I figured while I had the timing light out at the shop today I would check
timing on my 86 GXL. It’s been having a weird searchy idle and random misfires so I figured why not.

i followed the book and hooked up to L1 and shot the pulley, set the light to 5* and saw the mark line up perfect. Good. (Worth noting, every time my engine misfired the flashes would miss too while on the leading side. New plugs and wires. Possible coil problem? What do you guys think?)

checked under hood and saw that the Trailing side should be set to 20*. Set my light to 20* and hooked up to T1. When I shot
the pulley the Mark was WAY off. I fact it didn’t line up until I turned the dial back to 0. This seems strange as the Leading side checks out, I can’t imagine there’s any way to set timing for JUST the trailing side right? Is there something I’m doing wrong? Do you set the light to 20* before checking the trailing side or what? I’m fairly confused because I would expect if 1 was off the other would be off just as much. Any insight?

 

if the TPS is bad it can do this

 

Hmmm ok. I checked my TPS last week and everything was good, brought it into spec and it goes from 1k to 5.5k smoothly...