high idle and lean read out

[iLOL@Vtec]

ive been reading and reading forums after forums and stil cant figure out why my 98 gst wont idle right. when car starts idles about 1200 then a minute or so later jumps up to 2000 and my air fuel ratio reads a very lean mixture.also car is drinking gas horribly like im not bs ing but I get less than 9mpg also did a boost.leak test and nothing so I ran out of ideas. any help please.

 

[cola]

does it bounce between 1200 and 2000?

sounds like a bad TPS to me

 

[iLOL@Vtec]

yup but the crappy gas milage ? yea it wont bounce it will steady be at 2000

 

[cola]

if youre sure theres no boost leak its is definitely a sensor, do you have a CEL?

 

[Diamond Star Werks]

Your running in open loop mode reason for gas mileage. You have a vacuum leak, bad tps, misadjusted tps, bad isc, etc. Need more info like leak tests, cel? When it started, what your were doing to it before it started.

 

[iLOL@Vtec]

tested my isc checks out good also tested tps sensor good also
I adjusted the tps and dropped idle back down to 1000 but still idles bad and smells like its running insanely rich

when I baught the car it was stock still is stock but the upic had a boost leak fixed that and still did a booat leak test and fixed all my small leaks I can do another just to make sure also no CEL

 

[Diamond Star Werks]

Check your o2 sensor to be sure its oscillating like it should. Unhook your battery for ten min to reset ecu and fuel trims.

 

[iLOL@Vtec]

how do I check my o2 sensor ?

 

[Diamond Star Werks]

With a multimeter checking the signal wire. It should constantly switch btwn .2v & .8. Oh find s someone wroth a scanner that well show a datastream.

 

[iLOL@Vtec]

yea o2 is bad I dont get a reading and now my car wont spool ......