Idle problems

My car's acting weird ... it has started to lope during idle as if i had huge engine with a performance cam.. help please

91 celica st
4a-fe

probably the same thing mine is currently doing, check your ignition timing, if not make sure EVERYTHING in ur ignition system is good, that could be the other problem, after that check back here

could also be a loose or cracked vaccuum line

ok so which vaccuum line could it be? my vaccuum sensor or map sensor or whatever it is broke so i siliconed a new nipple on it and connected the hose and every few months it will slip off and idle drops to like 200 rpm and it spits black smoke ... and also ... how can i double check to make sure everythings hooked up right? i had a friend help me with my engine swap when i blew it and i'm not sure they even checked ... thanks

oh and what is good timing? isn't it like 10 degrees advanced for stock?

oh and what is good timing? isn't it like 10 degrees advanced for stock? i have the 4afe by the way

yea its 10 degrees btdc

and yea check all vaccum lines, one line falling off could make yoru car run like shit, theres a vacum line diagram on the bottem of your hood

My car's acting weird ... it has started to lope during idle as if i had huge engine with a performance cam.. help please

91 celica st
4a-fe

Could be an oxygen sensor perhaps?

it wouldnt idel like that if the o2 senser was bad...but hen again it mabe could. your car would start thrwoing codes with a bad o2 sensor...all it would do is if it was bad, the car would run pig rich, thats it