1997 Jeep TJ 4.0 idle and whine help

[Itygr]

I have a high-pitched pitched almost electrical sound for a short time after start which is new. When going downhill only the jeep sometimes idles quite low, almost stalls unless the engine is rev'ed. Recently done spark plugs, tps, cleaned iac. doesn't look like leaks, the high-pitched whine is new, just a few days. The Weird idle on downhill a few weeks. Any insights?


1997 Jeep TJ 4.0.

 

[Chris]

Sounds like a vacuum leak. Time for a smoke test.

 

[Itygr]

Shoots

 

[Itygr]

Smoke test and no issues, but now I have a new problem, that probably has always been the issue. A code finally showed! P0135. Upstream o2 bank 1, sensor 1. This will probably fix my issue, but I cant find an NGK 23151 Oxygen Sensor in stock anywhere. I've gotten a lot of feedback saying only use NGK, but other brands or types? Denso?

 

[WVJeep304]

Smoke test and no issues, but now I have a new problem, that probably has always been the issue. A code finally showed! P0135. Upstream o2 bank 1, sensor 1. This will probably fix my issue, but I cant find an NGK 23151 Oxygen Sensor in stock anywhere. I've gotten a lot of feedback saying only use NGK, but other brands or types? Denso?

I think the new number for the NGK/NTK is 23179. I've seen it mentioned a couple of times, but have no first-hand experience. Maybe someone else can confirm.

 

[Itygr]

I think the new number for the NGK/NTK is 23179. I've seen it mentioned a couple of times, but have no first-hand experience. Maybe someone else can confirm.

Great to know! Maybe someone can confirm . It looks right

 

[macleanflood]

Walker and Denso should be ok. I put a Mopar in my 97.

https://wranglertjforum.com/threads...ngler-tj-oxygen-o2-sensor-thread.4068/page-37

-Mac

 

[Itygr]

The answer was upstream O2 sensor. $50 and 10 minutes. NGK23179