Cylinder 3 & 4 Misfire

Hey guys I’m new to this forum so I’m new to how these things go, I’ve read a few threads but none seem to be quite the same senecio. I just bought my truck 3 months ago and have only really driven it to the desert and around town.

So here goes my problem. I was driving to my fiancés house yesterday when my truck started to shake violently at a stop light. Luckily I just so happened to be in front of an autozone and I wasn’t sure what the problem was, but I was out in the desert the day before so I was assuming it was the usual. Dirt in the MAF sensor so I bought some cleaner and a new filter while I was at it. Got back in the truck still had the shake. Let it idle for a couple minutes at this point I figured I had a misfire sure enough unfortunately I was right. It initially threw a code for misfire on cylinder 4 so I walked back into autozone returned my MAF cleaner and bought 6 spark plugs and swapped them in the parking lot (because I haven’t swapped the plugs since I bought the truck). Still had the misfire so I figured it wasn’t going to be a autozone parking lot fix and drove home. It was very weird I didn’t feel low on power and above 2k rpm it felt smoother than normal.

Today when I got home from work I hooked up my scanner and was getting cylinder 3 and 4 missing now. So my immediate thought was the ignition coil and swapped them around and got cylinder 4 miss again, assuming if I ran it long enough I’d get a code for cylinder 3. This is where I’m stuck. Could be the wire plugging into coil on cylinder 3, could be fuel injectors, could be worn pistons, and could be a timing belt problem. I can’t imagine pistons on 3 and 4 would go out at the same time, same with fuel injectors so I’ve pretty much ruled those out. And am left with timing belt and the wiring before cylinder 3 coil.

Am I Naïve for ruling out worn pistons and fuel injectors?

How could I check the wiring going into the coil? I am really just trying to avoid and prying the timing belt is fine (previous owner told me it was done 20k miles ago but you never know who Is BSing you). I’m hoping to get my truck up as fast as possible being from socal this weekend is Glamis opening weekend and was really looking forward to my trucks Maiden voyage and was hoping it would be opening weekend but with my luck it looks like it won’t be.

sorry for the long winded post but coming from a ford diesel forum nothing was more annoying than a vague post.

 

Time for a leak down and compression test

Cyl3 and cyl4 are on opposite bank and uses different coil pack

 

@02hilux compression test is on the menu for tomorrow will get back with you all tomorrow.

 

If compression and leak down result are good, I would send the injectors to Mototwest for flow test and cleaning. At this time, it's not a bad idea to change the fuel filter.

 

@02hilux compression test ✅ all cylinders in spec leak test ❌ leak test was not very good on cylinder 4 which had me very scared but I texted my uncle who’s a mechanic and he reassured me that the seal in the cylinder is not the only place air can escape he recommended a STP valve cleaner. I was skeptical but after about 15 minutes here I am with a smooth idle and a happy face. Drove my truck around the block and had very shaky acceleration. So I am assuming (and I’ve read up a little online) all my plugs were fouled during the cleaning. Luckily my uncle had the foresight to tell me to swap in all my old plugs. So tomorrow the old Tacoma will getting her new plugs back and an oil change (also recommended online) and hopefully crossing my fingers she will be running like new. I’m very excited because that’s the smoothest I’ve ever heard that truck idle but trying not to give my hopes with this gimmicky fix.