Rough Idle and Dummy Lights

Howdy! I have a 2019 TRD Sport (SR5 essentially with sway bars) with the 5.7L regular gas engine and about 65k miles. She drove perfectly fine two days ago, but this afternoon on a cold start she was idling real rough, like I immediately noticed it. As soon as I put it in gear, dummy lights lit up. I have a check engine light blinking, and the info screen says the collision system is down and that the trailer braking isn’t functioning properly. She’s always had regular oil changes with the level and color looking good right now when I checked. No other fluids leaking that I can see. I’ve had a rodent problem before in the winters but thought I fixed that with some thick metal grating that I screwed on to that cabin air filter entry point. I’m out of warranty (no extended) so trying to fix on my own if I can. Any recommendations where to start?

 

check your MAF connections and look in your Airbox...

 

No oil or anything else of note in the airbox or MAF

 

Ordered an OBD-II scanner to pull the codes. I have a feeling it’s a misfiring cylinder from a bad plug or CP but we’ll see

 

Cylinder 8 misfire. Time for a tune up

 

New plugs and a new coil, you'll be back!

 

Well after changing the the plug and coil pack on cylinder 8 (passenger side closest to firewall), it’s still throwing the same code and idling rough. My next guess is wiring or at worst a blown head gasket. Mother trucker…..

 

Check grounds from engine to firewall, et Al...I feel it's a wiring challenge...any worn wires under airbox, itself? MAF plug is snapped in with an audible "click?"

 

Cold weather, sudden change overnight, previous rodent issue, my guess is some wiring damage from rodents again. Worst case scenario would be head gasket (unlikely, but easy to test) or broken valve spring on that cylinder.

 

Yeahhhhh as I got a better look and really inspected the area, there’s definitely more damage from these dumba$$ rats or whatever is getting in there. I can work on mechanical stuff, but I’m a complete idiot when it comes to electrical. Need to get a voltmeter to begin with.

 

I share the same regard..."it's easy!" they say, but yeah, not my thing...I had to redo some chewed on ECM wiring and mak, those hair-like wires made my hand of thumbs super "functional!" I wish you luck...rough idle would make me think to check the MAF harness first...

 

He has a code for cylinder #8 misfire. Probably not MAF related.

 

Update: checked the voltage to the CP and read a 13.7V drop in voltage so the wiring there was fine. I figured the next thing could be wiring to the injector, but with a toddler this guy ain’t got time to pull the fuel rails. Took it to a Caliber Auto who confirmed the wire to the injector was chewed through. They’re pulling the fuel rails and replacing the wiring and harness for that injector. They’re also spraying an anti rodent chemical in the engine bay. $532 OTD which is a steal if you ask me. Hopefully that’s the only wire and the spray works

 

Daaaang! That's a great deal and bravo!! Time to make sure your friendly mice stay tFO, now!