RPM's Plummet when stopping
 

When i am cruising along at around 40 miles an hour coming to to a stoplight, and i let off the gas and start applying my brakes, my rpm's go from around 2000 rpms and plummet suddenly down to 500 rpms, and when i stop it feels like it is ready to stall. I have read through the search an d have found 2 possible problems. Ignition coil and IACV. Anyone know which of the two is more likely for it to be? and i have a haynes guide, so i can test both of them, but i dont really understand it that well for what i should do(IM DUMB). Any help would be great. I would really like to get my idle problems solved.

Re: RPM's Plummet when stopping
 

The condition you describe makes it very unlikely that an ignition coil is at fault.

A faulty IACV (idle valve) *could* be the problem, but instead I think it's likely either a uncalibrated throttle sensor (TPS) or a throttle body that needs to be cleaned. Why? If the voltage from the TPS is high enough, the ECU will think you are on the gas when you're not. The ECU will then keep the IACV idle air position valve closed. If the throttle really is closed all the way (you're off the gas completely) but the V is too high, the engine will try to die because it's starved for air. The ECU then reacts and opens the IACV idle valve and the engine idles normally. The fix for this is to first clean out the throttle body. Do a search here to find a write-up. The next thing to do when that is complete is to check the voltage from the TPS when the throttle is completely closed. I believe the allowable range is 0.35 to 0.65 V. If it's over 0.65, that is the problem. The TPS should be calibrated to ~0.55-0.60 for best performance. Calibration is done by loosening the two screws that mount the sensor to the throttle body and rotating the sensor slightly until the voltage is where you want it, then tightening it down. A service manual will provide full instructions.

Has your check engine light lit up at all lately? If not, I would still check it for the codes. To check your ECU for codes, Click here.

Already tried that
 

I already pulled the code, and turned out to be the 05 05, which means there are no faults recorded. So that didn't help. Ill try cleaning the throttle body, but I really dont think that would cause it to be that bad cuz i cleaned it just about 6 months ago. Dont know how it would get so clogged up that fast. So ill try that TPS thing you guys were saying.

Re: Already tried that
 

find out what the idle rpm is set at. The ecu will try to return it to normal but your rpms will dip if it is set too low.
Warm the car to normal operating temperature, turn off the car, disconnect the tps, restart the car and rev it to 3000 a few times before letting the rpms settle to idle. Adjust the rpm with the throttle plate screw if it is off a lot or with the IAC idle adjustment screw if it is off a little. Turn off the car and reconnect the TPS. See if the car's rpms dips now.

My 5 speed manual was doing something similar to yours. Found out the idle was way too low. No problems after resetting the idle.

Re: Re: Already tried that
 

I dunno, im tempted to just bring it to the dealer and have them try to fix it. my brother tried to fix some stuff on his truck a while back and ended up causing more problems that way so i dont know how much i wanna mess with it. But how much do you think that the dealer would charge to correct this problem? i wanna see if it would be worth it or not

clean your throttle body..

Re: Re: RPM's Plummet when stopping
 

do exactly this^

$20 says its the throttle body

make that $25 ;)

I had this problem last month. I cleaned my throttle body and replaced the fuel filter. No more problem.

Yeah. What he said. I need to clean mine again because it is doing exactly what you have described. I wonder if there is something extra in winter gas that gets the TB clogged quicker?

same problem here and its NOT my throttle body!!
just cleaned it yesturday.

sorry Sprint:kiss:.... now wheres my $20

BTW: how much would a TPS sensor and a new IACV run me?

Ant

no soup for you.. i said it was his problem :p

:bawling:

Ant:(

I forget the IACV price but think it was expensive from posts I had seen before.

SuDZ