Jlevansjr

I replaced the blown engine n my 1998 malibu ls....it is the 3100 engine. I found an exact replacement with only 30k miles.....connected all sensors and have been driving the car. The only problem I have encountered is a drastic drop in gas mileage. With the original engine I got 30-35 mpg....with the replacement engine I get only 24-27 mpg....so I went from about 330 miles per tank, I now get about 270 miles per tank. It seems that I have to press the accelerator further for it to respond...so it isn't as sensitive as it was before. Is there any throttle cable adjustment I need to do? No check engine light is lit...no sensor lights are lit...car runs fine otherwise.

Thanks in advance

Jamie

tech2

maybe do a compression test on this like new engine


came out of what year and model?


did you get the engine from a reputable recycler

Jlevansjr

Compression test was good.....engine came out of a wrecked 98 malibu....got it thru advance auto....

tech2

what were the numbers?


can you view fuel trim? what does the trim do on a hard accel

Jlevansjr

rats....don't remember, I could do it again....

On fuel trim.....I have no idea what ur talking about on that one...

tech2

do you have a scan tool that can view live data.

fuel trim is a measurement of how fuel is metered into the cylinders. it will show if the ecm is adding or reducing fuel to meet the ideal fuel ratio. if the mpg is bad, trim may provide information.


with lack of power problems; I would start by checking fuel pressure

Jlevansjr

I only have ne of those check engine scanners.....I hate to keep bothering you but I'm learning.....I don't know how to check the fuel pressure...how do I do that?

tech2

you will need a fuel pressure gauge