Car suddenly "overheating" and then not, repeatedly

[M_Anthony]

N55 engine, 100k miles, water pump and thermostat replaced last year (about 15k miles ago). Car has standard mods (JB4, intake, exhaust, etc.).

Went to take the car out for a drive today, and after about 1 mile down the road I get a notice on the cluster about water temps being high; yellow light first, then red light. I look at the oil temp gauge on the cluster and it's flying all the way to the right side. Car went into limp mode; I immediately pulled over and turned the car off; I also turned the JB4 off and went back to stock maps.

Let the car sit for a few minutes and turned it back on; oil temp showed completely cold, car was fine. I started heading home. Water temp light came back on, oil temp needle swung to 3/4 position (~300F), car went limp. Turn off and wait a few minutes.

Turned back on a second time, oil temp needle moves a tiny bit, water temp reports normal. Drove the 1/2 mile home. During this 1/2 mile, the oil temp kept sweeping from far left to far right, car would go into limp mode and then immediately stop being in limp mode, lurching forward with full power.

I really doubt my oil was actually at 300F after a mile of light driving...so what could cause this? Thermostat stuck open? New water pump going bad? Electrical gremlin?

[Petro135]

Sounds like something is loose. Water temp, oil temp going back and fourth. Limp mode going on and off. I'd pull the jb4 out and see if it gets better. Or check for loose battery connections first

[M_Anthony]

Originally Posted by Petro135

Sounds like something is loose. Water temp, oil temp going back and fourth. Limp mode going on and off. I'd pull the jb4 out and see if it gets better. Or check for loose battery connections first

Loose wire or something seemed like a good bet, so I decided to go check the engine bay. Noticed a tiny piece of foam near my intake.

Took the engine cover off and...I think I found the problem.

Car's been sitting for several weeks. Looks like a critter got into the engine bay and started eating the foam under the engine cover. It's everywhere. I don't see any droppings, so not sure if a mouse or something else, but I'm guessing whatever it was also ate through a wire in the process...

[Petro135]

So it literally could be "electric gremlins" lol.

[M_Anthony]

Originally Posted by Petro135

So it literally could be "electric gremlins" lol.

Pretty much, yeah! The two side effects I've noticed so far...TPMS is suddenly registering all 4 tires as low, despite them being at proper air pressure and brand new TPMS sensors/wheels.

Coolant/oil temp reading wonky.

Going to blow all this junk out of the bay tomorrow and then see if I can tell what's going on. Might need to get it towed to a shop if I can't figure it out myself.

[dtla1]

Originally Posted by M_Anthony

Pretty much, yeah! The two side effects I've noticed so far...TPMS is suddenly registering all 4 tires as low, despite them being at proper air pressure and brand new TPMS sensors/wheels.

Coolant/oil temp reading wonky.

Going to blow all this junk out of the bay tomorrow and then see if I can tell what's going on. Might need to get it towed to a shop if I can't figure it out myself.

Would love to hear/see the outcome of this. There's a ton of important wiring under the cowl there.