I have a 97 SS with approximately 120,000 miles on it. After cleaning the throttle body (without pulling it off) I had a high idle problem and a Service engine light. Now I have some technical knowledge just not an Autotap or other device for pulling codes. I know the first thingS to consider would be IAC or TPS. The service engine light has gone out a couple of times and was out when I replaced the IAC last Saturday. The idle seemed to be better, but it idles high when first started and slowly comes down during a 15 second period or so. The light has returned and I have also replaced the TPS. O2 sensors were replaced about 8,000 miles ago. I am wondering what the likelyhood is of it being the EGR given the miles and initial idle problem? any hints would be appreciated. Sorry for the long post I just like to give as much info as possible.

 

Get to an AutoZone or AdvanceAuto, etc to get a free code check. This will narrow the search for the cuprit.

I would suspect an air leak since it just started since you worked on the TB. It could be associated with the IAC.

The EGR could be a problem also. Heck with your miles, you could just replace the EGR. If it is not the problem, you may have avoided a future problem if you are running the oem one.

 

Thanks for the reply. I had no idea they would pull codes for free. As far as when the problem started...it wasn't after puling the TB it was after cleaning it with it still on the car. None the less, thanks for your help. That's why I love these forums. Good advice and a new set of options.

 

I've seen several posts from people who cleaned the TB, and ended up with no lube where the blade shaft rotates in the body. It can be enough friction to keep the blades from closing fully. That would give you a higher than normal idle, and could set a code for the "closed throttle" TPS voltage being too high. Try lubing the shaft at all points where it rotates in the throttle body.

Did you remember to put the little foam plug back over the shaft before you put the TPS back on? Are you sure all the gaskets are correctly in place, particularly the TB-to-intake manifold, and coolant/IAC plate-to-TB gaskets? Do you have the rubber hoses on the passenger side of the TB connected correctly?

No substitute for a scan, which would give you an immediate answer. There are OBD-II code readers available for as little as $50.

 

Thanks Injuneer I will lube the throttle plate shaft tonight and see what happens. I did install the gaskets correctly and never removed the foam when replacing the TPS. I also did the coolant bypass from the throttle body too, but I have never heard of any problems associated with that. What kind of aerosol spray would you recommend using to spray around vaccum lines and throttle body to check for leaks?