BAAD gas mileage

**big red** · 12-13-2007, 07:59 AM

My 1997 S10 has all of a sudden take a nose dive with gas mileage. its a vortec 4.3L ZR2 package 4x4 ext cab. i know they don't get the best MPG ever but i should be getting better than 10 mpg city. the only thing i did was clean the throttle body 2 weeks ago. it was gummed up so bad, i figured i would be getting better MPG or at least better throttle response but it is the opposite here. no check engine light or anything like that. i am sure i put everything back the way it was before the cleaning. any ideas?
thanks
ricky

**retired2001** · 12-13-2007, 10:33 PM

"Assuming" that you got everything back where it belongs, you might try disconnecting the battery and see if it will "reset" the computer. I know that I have changed spark plugs before and not "reset" the computer and the new plugs didn't help. May not be your problem, hope it helps!

**84fiero123** · 12-13-2007, 10:41 PM

Just how did you clean the throttle body? Not with a tooth brush I hope. The inside of the throttle body has a coating on it that can be damaged if scratched.

You may also have cracked a vacuum line when moving thing around.

Take a spray bottle, like a Windex bottle and spray water around any vacuum lines with the engine running. If the idle rises when doing this you found a vacuum leak.

I like using starting fluid to do this but there is a fire danger using that so unless you are prepared for that I would not recommend it for you.

**PepboysASETech** · 12-14-2007, 12:53 AM

Another good one to test vacuum leaks is brake cleaner. Its cheap and its really light weight and doesnt leave a resadue. While the engine is running and you spray it into a known leak the engine will run really rough.

**Cap** · 06-16-2009, 07:52 PM

what effect is that going to have on the engine. being it's solvent degreaser?

**Jimmiee** · 06-16-2009, 08:13 PM

Make sure you didn't leave a temperature sensor wire off. This can keep your truck in open loop which really sucks up the fuel. Also, You may want to check your computer for any codes. I'm willing to bet you have a code stored in memory or at least a pending code. If so it will give you a place to start looking for your problem.

**mattpresley** · 11-08-2009, 12:41 AM

Had this problem with my Ranger. I don't know much about the s10's egr system but my gas milage issue ender up being a bad DPFE sensor

**s5belford** · 11-08-2009, 09:34 AM

I had a 95 Jimmy with the 4.3 and couldn't get better than 11 in the city to save my soul..... :(

**TRPLXL2** · 11-08-2009, 07:25 PM

I honestly never thought I would have a truck with worse mileage then my 6.0 Silverado, and then they made the 4.3 and low and behold we have a winner! When I bought my S-10 the dealer tried to talk me into the 2.2, and I told him there was no way I was getting a 4 cylinder in a truck. I don't regret it either I love that motor, I have never checked the mileage but I know it costs me $75 a week in gas to go to and from work.

**s5belford** · 11-08-2009, 07:57 PM

Originally Posted by TRPLXL2

I honestly never thought I would have a truck with worse mileage then my 6.0 Silverado, and then they made the 4.3 and low and behold we have a winner! When I bought my S-10 the dealer tried to talk me into the 2.2, and I told him there was no way I was getting a 4 cylinder in a truck. I don't regret it either I love that motor, I have never checked the mileage but I know it costs me $75 a week in gas to go to and from work.

that 4.3 is a rock solid engine but the gas milage is really bad! if I ever end up owning another small suv or s-10 I'll throw a small block in it!