Ive got a little bit of a problem. I have a 1999 s10 blazer 2 door 4wd, its got about 68k on it. Lately it has been struggling to get up the hill i live up (about 6%), i used to be able to go up it at about 65-70 no problem but now i have to put the pedal to the floor just to maintain 50 and i can feel it not agreeing with the speed. Since i have to go throttle wide open my gas mileage has dropped from about 12-13 to 8-9, it is bad. I live in VT so it is cold, does that have much to do with it? Has anybody had the same problems and if so what did you do to fix it? What can i do to get a little more performance out of my engine?

Any help or ideas would be great! Thanks alot!

 

Some things wrong, any other symptoms, codes, odd tanny shifts, hard starts ect.

 

might check the m.a.f

 

@spitty bays-- i have been having hard shifts, but it is not all the time...ill be going up the hill pushing it in 3rd and then it will do a hard shift out of 3rd into overdrive, but i always thought that this was just because i was going up the hill and the gearing is just not quite right...could it be transmission?

@99blazer99 -- thanks for the idea, but im sorry what is the m.a.f? sorry if that is a stupid question.

Thanks for the replies!!

 

i have a smiliar issue. gas mileage has changed for the worst and performance has decreased.

anything else it could be besides MAF?

 

MAF is mass air flow sensor its on top of the motor were your main air comes in, white metal circle about 3". It will be after the air filter wright were plastic goes to metal on the motor. I think yours has one mine does not (older). They have fine platinum wires and a screen. They can be cleaned with MAF spray cleaner. Be carefull the part is expensive. Now #1 check tranny fluid, procedure is in your owners manual. You don't have to be that low to have all those symptoms...first thing before you drive it again, tranny costs more then MAF!

 

Thank you, i will definitely check the tranny fluid. I would hate to put a new tranny in it.

 

Not sure about 99, but on my 97 I experienced the same drop in milleage/performance. Slowly over a year or so. There is one simple thing with these engines, Closed Loop or Open Loop fuel mode. This can be read from a scan tester, I use a PC version.

Open Loop is when it thinks the engine is cold. Air/Fuel ratio is calculated using coolant temp and MAP/MAF sensors. It goes to Closed Loop based on O2 temp, coolant temp, or time (unspecified). Air/Fuel can range from 0.8:1 (over 50% fuel) to 16.8:1 (around 5% fuel)

Closed Loop is when it thinks it's "warm". Air/Fuel ratio is calculated using O2 and "other" sensors. It will enter Open Loop again if O2 cools off, or other sensor failure. Tries to maintain 14.7:1 air/fuel.

IF you remove the battery, or leave your lights on, etc - the engine computer will want to run some "non-continuous tests", these are viewable with OBD-II reader. Some of those must pass for it to enter Closed Loop (O2/CAT)

My problems started with coolant temp sensor, even though the engine was warm, the computer ran the engine like it was cold. After some time of driving like that, my CAT was bad. And eventually found out o2 sensors were bad.

Once all the sensors were fixed, and ECU tests completed, it still had to "relearn" the timing curves, which it should do in "normal driving". I've only just recently reached close to 20 MPG when I was down to around 10 MPG. And it definitely has more power on hills.