The car has been running fine but a few days ago i cleaned the throttle body, put fuel injector cleaner in the tank, and use sea foam to clean the intake with a vacuum line. once the car is at operating tamperature i begins to fluctuate idle from 900 to about 1200. i noticed if i turned the a/c on when it put a load on the engine it stopped.
I have removed the throttle body cleaned the iacv and the rest toroughly. tried replacing the ect sensor cuz that seemed to make it get a lil better when i disconnected it but no such luck. no vacuum leaks(that was my first thought). im a lil frustrated and out of ideas. Need so diagnostic help bad.

 

its your IACV Sensor! buy a new one! this is like the 4th issue about idle fluctuating lol

 

I agree. If you dont have a vaccum leak, check the IACV.

 

ya i had read that so i tried cleaning it first. because of putting those chemicals through it. about how much does that cost

 

$165.00 at autozone and idk how much difference will be at advance or w/e. don't buy a used one because its going to do the same thing and its just going to make it worse. might as well just buy a new one and get it over with.

 

replaced the iacv. didnt solve the problem. helped some but no solution. anyone got anything else

 

Try bleeding the cooling system.

Try unplugging the O2 sensor.

Any CEL codes?

 

no CEL codes and i wll go try the o2.

 

no air bubbles in coolant. o2 doesnt change anything. since i did that service throught the brake booster vacuum line so i check that and there seems to be a one way check valve and if i hold my thumb over it and pump the brakes(causes the idle fluctuation) it fix the problem. where can i get that check valve. i think thats my issue.

 

If you unplug the brake booster vacuum hose at the intake manifold nozzle and block the nozzle with your finger, does this alone fix the problem?

 

ya. thats why i think its that check valve. do you agree or have a different suggestion?

 

You have a vacuum leak in the brake booster vacuum hose or in the brake booster itself. The check valve would only cause this problem if it leaks.

Start by carefully checking the hose connections.

 

thats what i was thinking it has to be some where in that line. the main reason i think its the vavle is cuz the chemical through it and since the age and its plastic it may have messed it up. thats the cheapest option

 

Verify a leak from the valve and attached hoses before you replace it because the leak also could be from other parts of the hose or even the brake booster.

 

okay so i bought new clamps and hoses and replaced them. the valve seems to be checking out good. how would i test the brake booster for leaks? im still continually checking for vacuum leaks just incase. i leaning back towards the idea of a iacv because the one i got i found on craigslist. looked clean and came with an original box. bought it for $10 have the feeling i got screwed but it wasnt expensive. let me know what you think

 

alright went to the junk yard. bought some of the 88cent vacuum line check valves and didnt fix. tested the brake booster seems to be fine. guess that iacv i got was a dud and im going to order a new one today. if anyone has any other suggestions to try let me know. if i dont have to spend 165 on it and it be fixed that would be awesome. thanks

 

Blocking the IM nozzle that serves the brake booster fixed the idle problem, so you have a vacuum leak in that system somewhere.

 

thats what seems to be the issue. looking like ima need a new brake booster. i have replaced that check valve and all the lines with new clamps so a booster seems to be the issue. odd that it would just now show up after i serviced the fuel system. how hard of a job is replacing that? like how endepth?

 

Reconnect the vacuum hoses and do these tests:

 

so to do the leak test for the booster i hold the pedal down after running the engine? cuz i didnt that it may have rose a bit but im not 100% on how to perform this test.....may sound dumb but i am getting a bit frustrated with the whole thing

 

It would be most informative if you do all the tests.

The first leak test is started with the engine running and the brake pedal pushed down. While holding the pedal down turn the engine off. Does the pedal move up or down within 30 seconds of pushing on the pedal?

 

going to do that now

 

it passed the functional test and the check valve test. the leak test it seems to fail but it only has slight pressure on my foot

 

It seems that the brake booster is bad. Did both leak tests fail or only the first one?

 

only the first one