so i have a S5 NA thats surging at idle, ive eliminated vacum leaks with new gaskets, hoses, injector seals, and then tested twice, adjusted TB fast idle, thermowax and TPS, bypassed the fuel pump resistor relay with jumper wires, cleaned out and tested the BAC. I did change the stck airbox to a cone filter and heat closeout but doubt that would cause this, the car doesnt have the leding coil but will tommorow, people suggested i reset the timing, but i dint have access to a timing light for 4 days.
after switching the coil i was planning on loosening the CAS and turn it a little back and forth and see if that stops the surge.
but the car idles fine with the AC on, so that makes me think timing has nothing to do with it, but ive tried damn near everything else.
also the AWS is unpluged, is the passage through the solenoid always open when theres no voltage?

please please any help guys.

 

i know ive posted this problem several times, and tried all the sugestions, but they dont work
anybody?
any comments help

 

You likely still have a vac leak. Have you used a propane torch to check for leaks?

 

no ive checked with carb cleaner, witch is almost as volitile as propane

 

anyone??

 

Carb cleaner is a poor substitute for propane. Ether (starting fluid) works well, but is horribly explosive.

You mentioned replacing the injector "seals" - do you mean the doughnuts at the bottom tip of the injector or have you replaced the air bleeds/orings also?

 

i replaced the injector grommets and orings, if the air bleeds are under the grommets than the grommets are the final seal, right?

 

Leaking air bleeds will cause surging idle. Using propane near the fuel injectors under the UIM is the easiest way to diagnose bad air bleed o-rings. A car heat soaked in Phoenix is very likely to have hardened air bleed orings.

 

Did you replace the O-ring between the throttle body and upper intake manifold? that was my problem when I was having idle issues.

 

ya i replaced that

Leaking air bleeds will cause surging idle. Using propane near the fuel injectors under the UIM is the easiest way to diagnose bad air bleed o-rings. A car heat soaked in Phoenix is very likely to have hardened air bleed orings.

i guess propane has more a gassues state than carb cleaner, cause i sprayed that in gaps under the UIM but no changes to idle.

when i put the leading coil in it surges up on idle but surges down in double the time it used to.

 

I think you just solved my mystery vac leak. Thanks!