Sputtering on acceleration (fixed) now poor MPG. Any ideas?

So I was able to get my hands on a buddies ODB2 ready. It was pretty low tech so it wasn’t able to read current engine data but I believe I was able to get the information I needed. The code reader takes a “snapshot” of current engine conditions when a CEL is tripped. So I let the jeep warm up then pulled an injector plug to trip a CEL. This took a snapshot of the temp and other engine info. Here are the results.
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I’m now thinking that temperature isn’t an issue. So I’m troubleshooting poor fuel economy
 
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Take a temperature reading at the thermostat housing where the temperature sender is located. That will be the most accurate place for a reading.
 
Bennyggg said:
I’ll take a reading later today. Do you think I still have a temperature issue?
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The IR scan shows 187 but it is not in the actual coolant like the engine temperature sensor is. OBD scanner shows 194 so it appears your coolant temperature is ok. Did the outside air temperature drop recently. It has where I live and my last fill up was 1.5 mpg less than the previous tank. It typically runs a bit less mpg during the colder months.
 
Rich1961 said:
The IR scan shows 187 but it is not in the actual coolant like the engine temperature sensor is. OBD scanner shows 194 so it appears your coolant temperature is ok. Did the outside air temperature drop recently. It has where I live and my last fill up was 1.5 mpg less than the previous tank. It typically runs a bit less mpg during the colder months.
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I live in SoCal, although I think it’s freezing out it’s only about 45 at the lowest.
 
Ohh i wish i could help you.
When my Jeep started chugging fuel at a rate of galon/10 miles, i replaced O2 sensors along with switching to iridium XP985 spark plugs. MPG and power went up but never to the level it was. Before the issue i was hovering between 16 -17 mpg, after the fix 12-14 was the most i could get out of it. On top of that, it became sensitive to type and brand of gas i was filling up with.
I went though all sorts of delusional theories for over a year while chasing this issue.

About 4 days ago, a memory came back to me about iridium spark plugs. Roughly 6 years ago I had issues with them in Subie Sti, mpg dropped from shit to a hole full of shit.
So, 4 days ago i swapped to APP985, and so far according to a fuel gauge and OBD2 scanner, i am back to high 16 mpg range. Ill do two more fill ups before declaring it as a victory, but so far after putting it through all sorts of city/highway conditions, i feel confident that iridium spark plugs was the issue.
 
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eastbloc said:
Ohh i wish i could help you.
When my Jeep started chugging fuel at a rate of galon/10 miles, i replaced O2 sensors along with switching to iridium XP985 spark plugs. MPG and power went up but never to the level it was. Before the issue i was hovering between 16 -17 mpg, after the fix 12-14 was the most i could get out of it. On top of that, it became sensitive to type and brand of gas i was filling up with.
I went though all sorts of delusional theories for over a year while chasing this issue.

About 4 days ago, a memory came back to me about iridium spark plugs. Roughly 6 years ago I had issues with them in Subie Sti, mpg dropped from shit to a hole full of shit.
So, 4 days ago i swapped to APP985, and so far according to a fuel gauge and OBD2 scanner, i am back to high 16 mpg range. Ill do two more fill ups before declaring it as a victory, but so far after putting it through all sorts of city/highway conditions, i feel confident that iridium spark plugs was the issue.
Click to expand...
That actually is a big help. You are reminding me that I need to wait a few fill ups before I can truly see if I’ve made any progress. I appreciate the post. 🤙🏽
 
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