bad mileage

[chevyguy93]

My uncles got a 2001 (i believe) 4 cylinder sonata. He says he's been filling the car up every few days, yet he hardly drives anywhere. In other words, he's got some serious gas mileage problems. Also, he says sometimes the car feels as if it bogs down when under acceleration. I know lots about cars, but have never had to deal with a hyundai before.
He took it to a couple shops, and they said the computer read no problems.

Also, there has been no check engine light.
Any ideas on what the problem could be? I was thinking a bad O2 sensor or clogged cat?


Thanks in advance

[cmhj2000]

Without codes the one main culprit I've seen over the years are injector issues. Usually using a good injector cleaner like Amsoil PI cleaner does a lot if this is the case.

Cheveron Techron works well too but an oil change should soon follow with this.

[dmiller66]

Another thing you might suggest is switching engine oil to Amsoil (www.amsoil.com). My elantra is supposed to get 24 mpg in the city, and with the synthetic oil and synthetic universal transmission fluid I never get below 30 mpg. Others have also gained mileage just by simply switching to Amsoil. Hope this helps.

[frobotz]

Originally Posted by dmiller66

Another thing you might suggest is switching engine oil to Amsoil (www.amsoil.com). My elantra is supposed to get 24 mpg in the city, and with the synthetic oil and synthetic universal transmission fluid I never get below 30 mpg. Others have also gained mileage just by simply switching to Amsoil. Hope this helps.

Dont waste your money changing oil. It wont make a difference big enough to make it worth paying all teh extra money for amsoil. I use synthetic i get at wal mart for 1/3 the price of amsoil.

I suspect you have an injector issue.