98 TJ Sahara was driving fine until all of a sudden at ~45 mph the truck started surging. Came to a stop and it threw a check engine light and started to idle extremely rough with a strong smell coming from the exhaust. Managed to limp it to an auto store and they read the check engine code as P0171. Managed somehow to make it back home a few miles away, but it wasn’t a pleasant drive. I have a spare O2 sensor since I didn’t know when the last time it was changed was and was planning on doing it, but wondering if there’s anything else I should look at, or if a bad sensor on a 98 would even cause this kind of behavior (specially the surging). Thoughts?
Broke down with code P0171
- Thread starter Camhabib
- Start date
At this point I'd try replacing the O2 sensor. Make darned sure to ONLY replace it with an NTK replacement, do NOT use a Bosch O2 sensor. Make sure you only replace the Upstream O2 sensor as the downstream O2 sensor mounted on the catalytic converter would not cause your problem. The upstream O2 sensor is located just below the exhaust header on the downpipe.
NGK 23151 is what I have on hand, which from my notes is the upstream sensor which I have written is the only one that really makes a difference.
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NGK is fine, that's rarer to find but it's the same as the NTK... NGK owns NTK. And yep only the upstream sensor makes a difference in how the engine runs.
Probably going to sound like an incredibly dumb question but, the upstream sensor is the one after the exhaust manifold at the very bottom of the bay which you can see from above when looking down? I can take a picture if that description doesn’t cut it.NGK is fine, that's rarer to find but it's the same as the NTK... NGK owns NTK. And yep only the upstream sensor makes a difference in how the engine runs.
Jerry
Since I am pretty new @ this stuff- why only the NTK & not the Bosch? is it a fitment issue?
Since I am pretty new @ this stuff- why only the NTK & not the Bosch? is it a fitment issue?
I had a P0171 code back in August. Ended up being my exhaust manifold which had 2 small and one large crack in the welds (it was pretty old). Replaced the manifold, entire exhaust system and both O2 sensors (98 TJ).
It’s how the voltage on the sensor is referenced, Wranglers use a rather unique reference scheme and most manufacturers’ sensors won’t work correctly under those conditions. NTK happens to make a sensor designed to work using the the voltage reference (2.5v as opposed to 0v) that the Jeep requires.
Okay so I finally got around to replacing the O2 sensor and no change. The Jeep still starts up fine and then once it warms up, starts to sputter. Shutting it off and turning it back on, again, runs fine for a bit (30 seconds) and then starts sputtering again.
Is there anything that would give that code and cause the Jeep to run like that?
Is there anything that would give that code and cause the Jeep to run like that?
The reason it runs fine when first starting is the system is in open loop during the warm-up cycle and ignores the o2 sensor data, once it goes into closed loop it uses the information from your o2 sensors... As others have said make sure you don't have any exhaust manifold leaks...
If you have a shopvac or similar that you can reverse the port and blow instead of suck (sorry ), stick it on the tailpipe so you can blow air into the exhaust system. Take some soapy water in a spray bottle and crawl underneath and spray the manifold. If it's got cracks you'll see bubbles pretty quickly. That's how I found mine anyway.
), stick it on the tailpipe so you can blow air into the exhaust system. Take some soapy water in a spray bottle and crawl underneath and spray the manifold. If it's got cracks you'll see bubbles pretty quickly. That's how I found mine anyway.