bouncing idle

So my car is a 91 rs. The car has developed a horible bouncing idle. It will bounce from 750 to 2000rpm. It won’t do it until the car has come to normal operating temp and then it won’t stop. It still drives fine but when ever i put the clutch in it starts bouncing. The car has had this problem in the past but it would only happen for little while and then it wouldn’t happen again for a couple of mounths.
Here is the part that i find strange. I put some new cams in back in the spring and a couple days after my check engine light came on. It only came on the one time and then didn’t come back on again but i did check for codes when the light was on and i pulled code 43 which is fuel system supply. I checked for codes a couple days later scince the check engine light was no longer comeing on and drew no codes. Now after the problem started with the idleing i had no check engine light on but i check for codes anyways and i pulled the same code. I can tell by the way the car jerks at low rmp while it is in gear that this problem is probably a fuel surge but I’m not sure what is causeing the surge. I know it could be a vacum leak but i couldn’t find any damaged lines. I am compleetly lost and i could use any advice on where to start with this problem.

And yes i know that i can’t spell worth shit.

lol, not everyone can spell. it has to be vacuum somewhere…vacuum lines suck to trace…just replace all of them…they dont cost much and it solves prob down the road. however…on second note…you can cheat. the throttle body. look into the throttle body. there are two holes…towards the firewall side. one up, one down…both the same size…place your finger over the top hole…does the idle mellow out and even up? keep me informed.

Well I did the throttle body thing and when the top hole is compleetly covered the car stalls due to the fact that i’m cutting off the air required for it to idle. When im covered the hole about half way limiting the amount of air coming in the idle did drop and even out. dose this mean that the problem has something to do with the idle control valve? If so that would make some sence because when the car was idleing fine before this problem developed the idle was often between 1000 to 1500rpm.
Now once again I have a weird problem. as i was workinng on the car playing with the throttle body hole the check engine light came on after a while and then the idle settled at around 1500rpm and became steady. I turned the car off and then back on and the check engine light did not come on and the idle was steady. So i’m just not sure where to go next on this thing.

i would try to clean the IACV it may help the idle.

i would try to clean the iacv or borrow a friends that works and see if it fixes it. the pcv system would be to blame here…pulling smog into the intake…clogging the iacv and fuel injectors. clean the iacv and run some good fuel injector cleaner through the system…get back to me.

I’ll try cleaning the Iacv and the fuel injectors and see what happens. Any advice on which injector cleaner to use. I have used stp in the past but I question how well it works.

carb clean the iacv and if you feel adventures, remove the gas tank cap, and pull the fuel rail , remove the fuel injectors and carb clean them too…and if really wanna play…remove the intake manifold and carb clean it…just replace the gasket. i always use lucas fuel treatment…amazing stuff…just 3 oz per fill up…id use 6 for the first time…then the next few times just use 3.

I cleaned the IACV and added some lucas fuel treatment to my tank and the car is running good. The idle is still a bit high (900rpm) but it stays put at that. I didn’t have time to clean the fuel rail or the injectors but i will shortly. I should probably also clean the intake because when i looked inside it looked like the inside of a tail pipe. But non the less the problem is fix for now.

Thanks for the help

no prob buddy. yes, the stupid pvc system makes the intake tract disgusting. rip the intake manifold off there, and carb it too…car will run even better.

I’m going to have to because the thought of how nasty it is inside will cause me to loose sleep