Weird idle, when car moves it makes rpms go up…

Lately, when I get on the gas and let off, my idle gets stuck at 2krpm, I have to tap the gas and then it will come back down to normal. The idle also has slowly been going up from its normal 1200rpm to about 1600rpm, I adjusted it back to 1200rpm two times, the first time being about 2 weeks ago by using the idle set screw and today, after the second time, I went for a ride and noticed that if my car starts to move (ex: if I let it roll down hill or if I accelerate at all/if the car is moving at all) and I let go of the gas, it will stay at about 1500rpm and then climb to 1700-1850rpm and just stay there until I come to a complete stop where it will drop to 1200rpm and sit there. Has anyone ever seen this? Anyone got any ideas on what it could be? Other then that though, it seems as if the car is running good, getting a perfect 10psi boost to redline, power and everything else is normal.

Oh yeah, I disabled AWS already from when before I bought my car and I did check the slack in the throttle cable and its ok. Oh yeah I have a mp so my airpump is disconnected.


I was kinda thinking it’s the...
dashpot
ISC
AWS (but its disconnected)
Wax rod assembly
fast idle screw
*possibly* the airpump solenoid (but its disconnected)


anyone know how to test these? can you just block them all off and adjust idle via the fast idle screw as teamstealth did in this thread https://www.rx7club.com/showthread.p...ght=idle+raise ?

hwo would you block off the isc, do you just unplug it?
same as with the wax rod assembly.

anyone got any idea on how to test the Wax rod assembly?

 

k i tried to mod the above message but it did not let me so here is a revised post of the above.

Weird idle, when car moves it makes rpms go up…

Lately, when I get on the gas and let off, my idle gets stuck at 2krpm, I have to tap the gas and then it will come back down to normal. The idle also has slowly been going up from its normal 1200rpm to about 1600rpm, I adjusted it back to 1200rpm two times, the first time being about 2 weeks ago by using the idle set screw and today, after the second time, I went for a ride and noticed that if my car starts to move (ex: if I let it roll down hill or if I accelerate at all/if the car is moving at all) and I let go of the gas, it will stay at about 1500rpm and then climb to 1700-1850rpm and just stay there until I come to a complete stop where it will drop to 1200rpm and sit there. Has anyone ever seen this? Anyone got any ideas on what it could be? Other then that though, it seems as if the car is running good, getting a perfect 10psi boost to redline, power and everything else is normal.

Oh yeah, I disabled AWS already from when before I bought my car and I did check the slack in the throttle cable and its ok. Oh yeah I have a mp so my airpump is disconnected.
vaccum is the same when the idle is at 1200rpm but it is a bit higher as expected when idle goes up to 1700-1850.

I was kinda thinking it’s the...
dashpot (but i tested via the book/green shop manual and it tested out fine; fast out, slow in)
ISC
AWS (but its disconnected)
Wax rod assembly (but i dont think this has anything to do with the problem after the car has warmed up)
fast idle screw
the airpump solenoid (but its disconnected)


anyone know how to test these? can you just block them all off and adjust idle via the fast idle screw as teamstealth did in this thread https://www.rx7club.com/showthread.p...ight=idle+raise ?

hwo would you block off the isc, do you just unplug it?
same as with the wax rod assembly.

anyone got any idea on how to test the Wax rod assembly?

What does the isc do anyways? Do we really need it?

I bought some starter fluid tonight and will be spraying it all around the manifolds ends tomorrow to see if there is any leaks.

 

ttt

 

stuck/sticking/improperly adjusted throttle cable

gunk in the butterflies

 

skunks,

Is your TB coolant path bypassed and fast idle cam manually set, or is stock?

 

might also check the fast idle cam, mine was doing the same after i eliminated the aws, and i forgot to wire the fast idle cam open. give that a shot, now i can finally hear my port!

 

does anyone got any idea where the ISC solonoid is? im looking at the manual and i still cant find it. any pics?

the TB coolant path is stock and the fast idle cam is stock (at least i hvae never touched them)
how much are we suppose to wire the fast idle cam open? in anycase, i was kinda wondering how the fast idle cam could do anything as once the car warms up, the wax plug goes in and the fast idle cam just goes in/out a bit more. how could it raise the idle (it seems as the idle slowly pumps it self up adn then hangs at 1700-1850 rpm, kinda weird)

 

i could see these were the problem if the idle got stuck and would not come down but actually the idle seems to pump itself up to the level when the car starts moving (i dont need to apply throttle for it to go up such as if i let hte car roll down hill) when the car is stationary as i said, the idle is at 1200 which is fine for me. i also checked the throttle cable and its fine.

 

info on F49,F81 and F83

 

i read that teamstealth wrote on his thread that "The ISC is on the back-drivers side of the UIM. The part # mazda has for it is 20-660. And yes, i did block all of them off, and i jsut deal with the check engine light. You can use resistors to eliminate that problem though." i still cant find it though. pics please

 

ahhhh thanks for the tip on looking on page F81, i saw the other pages but some how missed that one, thank you

 

Any problems shifting lately? Stock clutch?

 

ok, i fixed it, it was the isc, i just disconnect it. the reason why i could not find it is that it was being hidden by the double throttle stuff. thanks for all your help guys