still a bad idle

[red93camaro]

ok i changed out the iat sensor and the idle air controle sensor. Wtf else is their ? when i start up it sounds like i have a mild cam in their when i don't, its just the stock cam so whats goin on ? today in town the car would just drop like 100-200 rmp n bounce back up to idle and then do it again help please

[Jeanda]

how does your ride run after it warms up?
what bout when your driving and you turn on your AC, does your idle drop very low?
sometimes stalls?

[red93camaro]

no when it warms up it still drops a 100-200 rpm then goes back to normal idle but its really bad the first start up of the day

[94Redbird]

I had a similar problem with my car recently where I would be driving along and all of a sudden the motor would lose power and the tach would drop... sometimes it would get over it and come right back up again but most times it would continue to bounce as I gave it gas and eventually stall. The problem was the crank module. I would also have trouble trying to get the car started again too sometimes after it would stall.

[IceBird]

I used to have a jerry rigged plastic intake that i made and it got heat soaked and soft then collapsed in on itself. That made my idle rough. But unless you have a cheap home made intake thats crap then this probibly isnt your problem.

[Jeanda]

"crank module"
could you define " "?

[hockeyman]

I had a bad IAC too at one point, but it still had a bit of a "lopey" idle even after replacing the IAC.
I removed the Throttle Body and found a ton of carbon buildup inside of it. I broke it down to it's bare shell and then I soaked the shell in a Degreasing Solution, scrubbed the carbon off, and then re-assembled it. Ran great afterwards!

I have a few TB's that I've cleaned. Here are two of them that I bought and cleaned.

[stlunatics2oo3]

try this first before buying a new part unplug your battery for about 10 minutes then hook it back up and start it up and put it in drive for 10 minute with you just holding the brake then shut it off for 10 seconds , start it back up and put it in drive for another 5 minutes and then shut it off.

this process is called an idle relearn and when you replace the iac, or anything to do with idle its a good thing to do afterwards

Jeremy

[Resident_Geek]

Is there a hissing sound from under the hood?

[Jeanda]

re: "Idle Relearn"
I dont think there is any point in doing it while your rides idle is miss-firing or timing is off.

[stlunatics2oo3]

well it states bad idle so i figured hell its worth a shot instead of wasting more money on parts

[red93camaro]

found the problem a wire was off which caused the car to idle rough and act like crap on the highway. but the other problem still remains when i first start the car for the first time that day and go down to the stop sign about a block from my house it wants to stall out drops to like 200 rm then back up to normal any idea's ? thanks guys for all your help

[94Redbird]

Inside the computer housing there is a crank module that plugs into the board. I'm not sure exactly what it does but I would assume it's something to do with firing times related to the crank position. To remove it you just unscrew the two screws holding a little plate on the housing... the module is right behind that. This is basically what it looks like except this one is for an LT1 or LT4.

http://shbox.com/1/lt4km.jpg

[98Camaro3.8]

Originally posted by 94Redbird:
Inside the computer housing there is a crank module that plugs into the board. I'm not sure exactly what it does but I would assume it's something to do with firing times related to the crank position. To remove it you just unscrew the two screws holding a little plate on the housing... the module is right behind that. This is basically what it looks like except this one is for an LT1 or LT4.

http://shbox.com/1/lt4km.jpg

That's the knock sensor module. Converts the AC signal from the knock sensor into a value the PCM can read to adjust the timing based on any detonation that may be occuring.

[speedzonwheels]

It sounds like the fuel pressure regulator to me is bad. Or the air hose connecting to it from the motor is. I had that fly off once and it caused horrible idles.