Power Loss and Poor Gas Mileage

[mortora]

3.0 V6, manual. Went from 23 down to 18 mpg. Power loss especially when starting off. Changed air filter, spark plugs, plug wires, fuel filter only has 15,000 on it. Check Engine light is not on. Any suggestions? O2 sensors??

 

[jaycheetwood]

Any recent adventures in the truck that would've led to something getting clogged or damaged?

did you notice the loss before or after plug change?

 

[mortora]

nah, no adventures...loss was before the plug change, it seemed to help with restoring some power, but mileage has not improved and power seems to be down again...I'm going to check the plugs again today, when I do my oil change

 

[jaycheetwood]

Any struggles with starting it up any timing issues? does the motor seem to idle properly?

 

[mortora]

no problem starting and seems to idle fine, at least if it is different I can't tell it from in the past.

 

[jaycheetwood]

im no mechanic.. but it could be a restriction someone.. it could be a vacuum leak some where in the intake or exhaust.. any new noises?

 

[mortora]

no new noises either. I'm going to go home tonight and change the oil, and listen to it and mess with it a little. The only odd thing I've noticed is I had to let one of those quickie oil places change my oil and when I checked the dipstick it seemed a lot more full, even beyond the max fill line, and I'm wondering if maybe this caused the problem and it is fouling out plugs. I'm no mechanic either just trying to avoid a trip to the shop. thanks for you input

 

[mortora]

I'm going to check hoses, etc. how do I check for vacuum leaks, etc.? any advice?

 

[jaycheetwood]

most mechanics will charge about 60 - 80 bucks to diagnosis it and that maybe your best bet.

 

[bikerboy]

60-80 bucks is pretty cheap around here. At our shop it's more around 120-140. And our shop isn't the most expensive around here either. Make sure that you don't have any brakes dragging. And yes the oil above the full mark can effect gas mileage as can the type of oil you use.

 

[Big Jim M]

23 seems a bit high for that ride...to me anyway. Have you changed tire sizes? If the plugs or wires are giving problems the result would be chugging, surging or/and a general feeling of the engine missing at some point.
If the engine seems to run correctly the only problems could be a richer mixture such as the choke is left partially closed or the timing is partly retarded.. Either of which would cause more fuel to be burned and might not cause the driver to "see" anything unusual with the general running of the engine..
However installing taller tires would cause the engine to run a bit more retarded timing which would have the same effect.
Big JIm