GXP866

So I cleaned my throttle body a few days ago figuring what the hell it probably needs done. Instead of taking it of and cleaning it the right way, like I should have, I manually opened the butterfly with the battery connected and sprayed the TB directly. I'm an idiot, I know.

Now I'm having this problem where if I'm driving down the street and let off the gas the car will coast around 1200 RPMs where as it's usually around 600 RPMs. If I come to a stop and wait about 10 seconds the car will begin to idle normally. But, as soon as I even touch the gas the RPMs will shoot back up to 1200. I should mention that it idles perfectly fine in Park. I've tried almost everything I can do to fix this such as Idle Relearn, Driving cycle, battery disconnected over night...twice, and removing TB and cleaning properly (too late now). I'm afraid that I've damaged the TPS for good...

I called a dealer and they suggested some sort of throttle position relearn using their Tech II. Only other option is a new throttle body completely.

I'm at my wits end and am completely stumped. What do you guys think? Has anyone experienced anything like this happening before? Any help is greatly appreciated!

blkchevyz

if its something with it needing to relearn might just unhook the battery for a while to reset it.

how dirty was the throttle body? could you of loosened some gunk up make it stick?
also might check to make sure all the connections are in, could be a minor vacume leak

91parkave

iTrader: (4)

I've done that **** plenty of times with no issues but never with the key on just disconnect the battery overnight reconnect in the morning should be fine

Edit lol I'll join the didn't read club


On a side note disconnect the harness turn key on and make sure you don't have anything touching gas pedal and reconnect once you turn the car back off. Otherwise a throttle relearn might do the trick.

blkchevyz

wow how did i not read that you already tried that stuff lol

besides checking for a vacume leak, does the throttle body snap shot like it should? or does it seem like the spring is weak.


also i've done that a few time as well with no issues.

Ill_Born_ss

In the under hood fuse box find and check the ETC/ECM fuse, it is next to the large AC relay. If it is blown replace it with the IGNITION KEY in your POCKET!
If it is not blown, with the IGNITION KEY in the ON position but engine off... Remove the fuse count to 10 and replace the fuse, now turn key to run position,(start the car) do not turn it off first. See how that is.

GXP866

Just tried that and scared the crap out of myself with the spark sounds but took it for a ride after that and it's still acting up. Monitoring the TPS's and Commanded Throttle Position I've noticed it's reading lower than before the cleaning. Like before the commanded would be at around 14 or so while coasting now it's at around 10 or 11 while coasting. Could this indicate anything?

I tried disconnecting the TPS harness just now but to no avail. Could this be a "computer-out-of-whack" problem or could it be I damaged the hardware?

I checked for vacuum leaks and found none. As for the TB I've never really seen TB's other than my LS4 but with key to on position and pedal untouched it is staying open the tiniest bit. If I press on the pedal then release it, the butterfly with shut completely then open up a tiny bit again. Is this normal? sorry for my inexperience.

Ill_Born_ss

The movement of the butterfly is normal. It is spring loaded in both directions and does not close completely when activated. Functions the same as a air idle speed motor in previous cars. Did you ever get to try the stock tune back in it? Can you monitor /log your throttle position , acc pedal1&2 and commanded with the key on only (no engine running) while logging slowly press the acc pedal all the way to the floor and then slowly release it.

91parkave

iTrader: (4)

At this point I'd just say go get the throttle relearn done unless you have hptuners then you could do it your self

GXP866

So I bought a new throttle body hoping to fix my high idle while coasting problem but it didn't work. Now I'm thinking about getting a PCM reflash to try and fix the problem. I'm out of ideas completely. Do you guys think a PCM reflash would do anything to fix my problem? Also heard something about my intake tube leaking might cause the problem. Thing is I have a CAI from CA inductions. I don't think this is the problem though. What do you guys think?

GXP25

iTrader: (3)

Yes, a vacuum leak would cause it to idle higher.

91parkave

iTrader: (4)

So have you gone to the dealer for the relearn yet like we told u? You could ask flash back to stock with your diablo tuner.and i d shoot him an email to have him go through your adaptive idle tables and ensure the coast down portion has stock values. As well as your idle coast down spark table.

Mrchevorlet

I'm having the same issues and I don't see anything about what the issue turned out to be... please help I've been trying to figure this out for a while now!