my car is a 94 cx with a dx motor 150000miles
has about 180000miles now
my car used to run fine until now

when i start my car cold its fine
when i go to the store or out of the car and come back when i start my car the rpm runs really high like 2.5 rpm but that's when the engine is already hot and not cold
sometimes when the engine is hot and i start the car it is fine and rpm is normal but that's
a 1 out of 10.
so the problem is when at 2.5 rpm it seems like its running rich or something but the main problem is when i put my foot on the accelerator pedal(at idle or in gear) the rpm suddenly drops down about .5 rpm and seems like its lost power then suddenly rpm goes up and seems normal. this only happen when im in first gear trying to pick up speed again from a stop or light. you drive it around for like 10-15 min then when at idle the rpm is normal again
@ 700 RPM and when i accelerate it is back to normal
also when this problem occurs i get it to second or third gear and floor it the car will stall and seems like it gonna shut off on me

i thought it was the o2 sensor failing on me but ive replaced that and its still there

if anyone has had this problem or knows how to fix it please help me out
thanks

 

Any CEL codes?

 

no CEL at all

 

what is the reason?

 

When you turn the key from off to ON(II), does the CEL turn on and then off after 2 seconds? Or does it remain on steady?

 

it goes off after 2 seconds

 

for what?

 

When were the plugs, wires, cap, and rotor last replaced? Have you checked the ignition timing with a timing gun?

 

check these;

-IACV (very possible for your high idle)
-TPS (also possible for your high idle and the sudden drop to .5k rpm when accelerating)
-MAP sensor (could be the problem for the sudden drop in rpm)
-Faulty wiring (a sensor listed may have come loose or gotten torn recently)

after you check all those, then it means your engines bad and you should just scrap the whole car as is!

 

also what ronj@ht posted

 

plugs and wires have been replaced since last oil change
plug gap already set too
timing is within spec
havent messed with the cap or rotor though


i was thinking maybe one of those sensors too but i have forgotten the spec voltage it measures


but my idle is fine when its running good and doesnt go up or down like most i heard of

 

maybe clean your IACV??

 

the one that connects to the throttle body or the one behind the intake manifold?

 

Just curious, when you did the swap what intake/exhaust manifold did you use? What ECU? Which injectors? May be unrelated but just curious

 

behind the intake manifold

 

i did complete swap all stock nothing changed
the problem occured after i have driven it 30k miles which is now

ok thanks