Here we are again with idle problems - even after I got rid of my JeepTB. Ok, stock throttlebody here:

When I accelerate (in any gear) and push in the clutch to shift, the RPM's still stay high, around 2.5 and even up to 3 RPMs - which makes for a rough shift transition.

Also, if the car is stopped and idling... if I rev the motor the RPM's will climb as normal, and fall... but once it comes back down, it will rev back up again to around 2 RPM, and back down to 1.

WTF? IAC? can I adjust the tip, or is it maybe the TPS? has anyone else had symptoms like this, and what did you do to resolve them? Thanks in advance

check all the vac lines. Mine did the same thing when my vac lines fell off.

if been fighting this battle for months now and i zeroed it down to my engine coolent temp sensor, what was hapening was my upper rad hose was dripping ever so lightly down on the sensor and shorting it out giving a crazy reading which in return made the ecu go nuts and screw up my idle, ive mapped all this out with my obd2 software and at times while running i was getting coolent temp of -600 degrees f. by unplugging and re plugging the sensor back in it reset the system i guess and everything runs fine but i had to seal the ect sensor connection so no more water could get to it. might not be your problem but ths is what caused a major idle surge and hang with my car and since i fixed the drip there has been no issues

ok i use to have radiator leak issue's before actually, the sensor could be sh*t now, so it wouldnt be a bad start i guess.

I will also check some vac. lines-

pretty annoying problem, isnt it?

yes very annoying but before giving up on the sensor have someone read your temperatures to make sure its malfunctioning try unplugging it and replugging it back in, its the top sensor in question

if I unplug it and plug it back in, and then start the car: should it act fine for a period of time?

yes as long as the sensor is good

i'll give it a shot, and let the fourm know the result.

unplugged it, plugged it back in... took er' for a spin and it still acted the same. at oreilleys here in town its only $13 for the sensor so I might just buy it.

but you know the molded plastic tube /line that goes from the top of the valve cover to the intake ? well, its got a crack towards the front closest to the valve cover, is this considered a vaccume line? would it cause this problem? thanks

if any tube, hose, whatever has a crack ,hole in it id be concerned and replace it anyway. you sure the sensor is 17 bucks, sounds kinda low to me, its like 40 here in orlando however the sender unit below it is like 12 dollars? anyway you can read your intake temps?

man, unfortunately i dont have any data loggers or anything like that to track down problems.

I just got done replacing the 2 relays by the brake fluid resivour which solved a problem I had where the car wouldnt start w/o priming it first and a bunch of crap.

but now im here where the rmp's will hang it seems like forever, and when rev'ed it will pulse (up, down - back up, down).

yeah thats weird cause thats exactly what mine would do, if i reved it the rpms would hang and even sometimes climb, while driving evrey time i went to shift cluch would go in and rpms would stay where they wer at or climb, at idle sometimes id be at 1000 sometimes 2000 but when id warm up id idle from 700 - 1000 it would literally loop up and down consistantly, i fixed the leak and replaced the sensor, even went the extra mile to hot glue where the wires go into the plug and electrical tap it so there was no way water would get to the wires. problems been ok for a while now, do this start your car and unplug your coolent temp sensor and see what it does it should loop like i mentioned above, plug it back in and you should idle fine. make sure to fix the cracked hose you mentioned above, might help, you might also wanna check your pcv valve and make sure its working correctly. just keep at it youll figure it out, oh and if you nont plan on going turbo soon id wrap your headers, they seem to throw alot of heat around under the hood, mine would get so hot eventually they baked my upper radiator hose and it went from rubber to brittle plastic like material lol. anyway good luck dont give up.
joe

wheres the pcv valve? and how would I know its working right.

im gonna need to buy a new hose (acutally molded plastic) thats on the top of the valve cover. what is it called?



actually, i am planning to go turbo. i've thought of wrapping the headers but i'd rather get these things fixed and continue to save up for at least a bottom end rebuild and turbo.

im not sure i know what you mean can you describe where it is at or do you have a pic?

Do a search, there was a good thread not too long ago about testing the pcv.

ah ok; its the molded/plastic hose that connects to the PVC valve. There is a crack in where it meets the valve cover. I think though I can replace it with some standard hose though.

as far as the PVC valve, give it a good shake? If I hear a rattle, its good?

ok, PVC valve raddles... I replaced the PVC hose that was cracked, AND replaced the Coolant Temp Sensor

verdict: seems to have worked! Yup, the idle no longer pulses, and it does not hang when Im shifting gears and such.

thanks for the recommendation and help!

I nearly typed at the end of the post "off of one problem and on to another" and thats what it seems like.

Because now, it seems like my car almost dont want to start. It does, but it just takes a few extra seconds...

tune up time

Also when you install your IAC make sure you install it with the piston all the way out so it would be closed. I had a similar problem and that fixed it. Just a shot..

best time so far 14.3 @ 101.1mph(no traction)
www.cnnmotorsports.com

ok, i have not messed with the IAC... should I take it off and unscrew the piston all the way out?

i think im also gonna pick up a new crank angle position sensor and cam position sensor.

I'm having similar problems, but not as severe. I've replaced the PCV valve, and entire hose, as well as the vacuum line coming from the top of the tb. I'm wanting to try to replace my coolant temp sensor, but I can't seem to find it. What does it look like/where is it located?

its immediately under the radiator cap

Hey, cool, thanks!

-Chris