Horrible Mileage...Dirty Throttle Body?

[Bigmikelakers]

Last month, I changed my Air Fuel Ratio sensor. I disconnected the battery to reset the CEL. Then after I started her up and backed out it felt like my engine was choking. Like it was trying to cut off. But, as soon as I put it in drive, everything is fine. Then a week ago waiting at a light, it decided to do the same thing. The RPM's for me are usually 600-700 at a light. But, when it feels like it wants to cut off, it goes under 500 RPM. And I'm also getting horrible mileage. I can put in a half tank and barely get 85 miles until the empty light comes on. The first few months I had this truck, I was getting awesome mileage. I thought replacing the sensor would fix everything but I guess not. Do you guys think its because of my throttle body being dirty?

 

[stevec5000]

Last month, I changed my Air Fuel Ratio sensor. I disconnected the battery to reset the CEL. Then after I started her up and backed out it felt like my engine was choking. Like it was trying to cut off. But, as soon as I put it in drive, everything is fine. Then a week ago waiting at a light, it decided to do the same thing. The RPM's for me are usually 600-700 at a light. But, when it feels like it wants to cut off, it goes under 500 RPM. And I'm also getting horrible mileage. I can put in a half tank and barely get 85 miles until the empty light comes on. The first few months I had this truck, I was getting awesome mileage. I thought replacing the sensor would fix everything but I guess not. Do you guys think its because of my throttle body being dirty?

Throttle body being dirty won't make it use more gas unless it's totally clogged up. Don't the engine computer tell you what he problem is? Probably a bad sensor or fuel pressure regulator. Anyway it's way too rich for some reason. I had a Mitsubishi that did that once and it was because the intake air temp sensor was open causing it to think the air coming in was below zero all the time and making the mixture richer for a cold climate even though it was over 100 F outside, kind of like having the choke on all the time. Maybe the sensor you put in was bad or the wrong kind or you have something hooked up wrong?

 

[Bigmikelakers]

Good point, maybe something is still telling the computer something causing my fuel to run lean. I'm going to have to work on this. Thanks.

 

[SJC]

I started getting nasty mileage after cleaning my TB. Did I mess something up? Cause now I watch my gas gauge drop like its a v8 or something

 

[Baja Runner]

Sort of sounds like a vacuum leak to me. You sure all your hoses are properly hooked up, no cracks, etc.?

 

[gs300tt]

Did you use an OEM sensor or one from a parts store?

 

[Bigmikelakers]

Did you use an OEM sensor or one from a parts store?

I used an OEM Denso sensor. Does disconnecting the battery actually allow the computer to recognize the new sensor or does that just turn off the CEL?

 

[SJC]

I am wondering the same thing^

 

[thor999]

I actually replaced my O2 sensor like three months ago and when I started it up, no CEL! Yet, I threw my first CEL in about 8 months just a week ago, disconnected battery yesterday and no CEL yet... will be installing Scanguage ll this week, I assume if there is a code present it will report, and in turn, so will I! :50cal:

 

[KHoffRunner]

I'm also getting horrible mileage. I can put in a half tank and barely get 85 miles until the empty light comes on.

How many gallons is that? Because my fuel light is very conservative and weird, I usually have about 4 gallons of gas left once my light comes on. How many mpg are you getting?

 

[JWaldz]

85 in the last half isn't unheard of.. I get around 110-125 the first half and 70-90 the second half. Then again I'm only getting roughly 15 mpg. It also depends on how heavy my foot wants to be. If you were getting a lot better mileage before you did the work and now it's worse then something isn't right. Go back and check through your work, maybe there is something you missed.

 

[Bigmikelakers]

85 in the last half isn't unheard of.. I get around 110-125 the first half and 70-90 the second half. Then again I'm only getting roughly 15 mpg. It also depends on how heavy my foot wants to be. If you were getting a lot better mileage before you did the work and now it's worse then something isn't right. Go back and check through your work, maybe there is something you missed.

Well, I haven't been able to fill my tank till now but it seems like I'm getting the same mpg's before my sensor died. I drove about 100 miles since saturday, including being stuck in a 8 mile traffic jam down in Seal Beach, and I am still at 3/4. Before when I was low on funds, I would put in slightly under half or even less and it seemed like the gauge would drop really fast.

 

[runnaz]

I have a 99 and it seems like last fall, over night my mpgs dropped quite a bit. I was usually getting 17/18. It dropped to 14/15 and I didn't do anything to it. The air filter wasn't very dirty, the sensors all seem to be clean. I even put a new fuel filter on it and it didn't help. It does have 182K miles, so not sure if its just old age or what.........