normally when i start my car the idle comes up to about 1500rpms then slowly drops down to about 750 or so. i no this isnt normal , but i hadnt noticed any problems till today. This morning when i started my car it went up to 1500 then stayed there. i shut it off waited a few seconds then restarted it. then the idle came down and it was fine. then i was going to leave my house after work and it did it again, but this time no luck when restarting it. it will idle between 1500 and 2000 and i already checked my tps and iac which have already been replaced.


My car is my daily driver and i need it to go to work so help is urgent.

 

let me know what it is when you find out what it was

 

sure.

- by the way my car is throwing no codes

 

vacuum leak ?
if it is intermittent probably not but hard to say.

 

sounds like a vacuum leak to me.

 

Hi, i do have exactly the same problem;
see my thread at : https://www.thirdgen.org/forums/tpi/...h-flow-my.html

most of them are telling me that i ve a vacuum leak,
but its not....... (i was also told to check the fuel pressure, but still not done)

I suspect the MAF sensor or fuel pump
please let me know if you found it out ! mine is also not throwing a code..

 

i have a throttle body air foil so that is already blocking the middle of the throttle body. i think i meant to put .075 and not .75. i think i know the problem now.

- a few weeks ago i was washing the engine bay of my car and the hose blew the wire off of one of my temp. sensors(the one in the head on the drivers side.) this caused my car to do the same thing(idle at 1500-2000 rpms) we discoverd the that it was the temp sensor because the scanner said that it was not going into closed loop even at 215 degrees mening the computer is not reading the temperature. now the wire is connected so i am going to replace the sensor and hope it works.

- if its not that than i think my egr is cracked and is leaking vacuum because every once in a while my car will throw an egr code.

-thanks for the suggestions guys
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that sensor in the drivers side head is the guage temp. sending unit. it doesn't have anything to do with the ecm.

 

just so you know this is perfectly normal. all 4 of my fbodies(2 TBI's, 1 MFI, and 1 TPI) do this on startup. it even says in the owners manual that upon startup the idles will be high and as the engine warms up the idle will drop.

as for the car just idling at 2000 it sounds like it could be an IAC valve. we put an iac valve into my friends delta 88 a few years ago and it idled up to 20 mph(we didnt have a tach for that car). im just guessing as to the idle for that car. i also believe that it could be a vaccum leak. try checking both of these.

 

well i will find out tomorow if the temp sensor fixed it, but i really think it will seeing as it did last time with the exact same symptoms.

i will keep u guys posted

 

It shouldnt fix it, I'd be more worried if it did fix it, that means you got some wiring issues.

It is indeed solely the gauge sending unit and is not even tied to the ECM at all... the ECMs temp sender is on the front of the intake manifold.