Howdy yall, my 1998 has had a problem for the past 6 months or so (I'm stationed away from home and can only work on it every few months, not being driven while I'm away), that started as a CEL. No problem, pulled out the scanner and saw a P0115 code for the ECT sensor. Wasn't the one on the dash, as the needle would move as it warmed up so figured it has to be the one on the sending signal to the ECM. Replaced it, it fired right up, but still had the CEL for the P0115. Confused I went about rechecked and unplugging then plugging back in the wiring looms I could follow. Now it's back to "new normal" of taking 15 or so seconds to start, then stumbling, and firing up as if nothing was wrong. What's really getting me now is the sound I'm hearing from the bay. Almost sounds like a plunger creating suction every second or so. Link to a video of the sound I'm hearing.

Has anyone experienced this before? I've searched through using the code and long start but can't find any posts (admittedly didn't search too hard) that contain both symptoms. I'm about to throw in the towel and take it to the dealer but know this community has been great and wanted to check with yall first.

Solved!

Wanted to post an update in case anyone in the future has this issue and their Google search leads here.

Threw in the towel after testing continuity of the ECT sensor and the wiring looms. Both were replaced, and it still threw the P0115 code immediately after clearing. Dropped it off at Toy-Lex in Webster, TX, and got the sense JP, the owner, knew his stuff. He let me know they narrowed it down to the ECU. While uncommon, it's also not unheard of for these to fail at random. I gave him the green light to do what he needed to do and replace it. I could have done it myself. It's an easy enough job, but I wanted to help out a small shop. After the ECU was swapped, everything was perfect.

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That's good to know! I have not heard of Toy-lex, but now I have another shop to recommend to people down there! Glad he got you fixed up. I agree that ECU is not super common, but happens often enough that I wouldn't doubt it.

I'd take my 4runner back there any day, easily the best experience I've had dealing with a shop when I get in over my head. I wish I still lived down there permanently to take advantage of the shop, but unfortunately I'm stationed across the country. The 4runner is still in my wife's hands down there so I might have her drop it off to tackle the few jobs I dont care to do.