car doesnt go over 30mph!

[kamel175]

i have a volvo 1999 s80 t6. car starts up fine but wont go over 20mph even i i floor the gas pedal. after letting it warm up for awhile , sometimes and hour or more, it will go about 30mph. sometimes the car will suddenly "catch" and then will run at normal speeds as if nothing was wrong with the car. the service light comes on when you first start the car then goes off after a few minutes. this year the car did not pass emission test. the printout from the emission testing place says:

READING: NO 1743.0 - FAIL
everything else read as pass. looking for some ideas as to the problem. appreciate any help. thanks

[kcjones]

Sounds like a large vacuum leak. Check all hoses. I didn't fully seat my throttle body intake hose once and had the same experience.