I recently purchased a 97 blazer. All was fine the first 2 weeks. Then came the SES light.
After taking it to find what code is causing the problem, I found it was 507 so I decided to clean the iac valve. While pulling the intake off I seen the throttle body was dirty so I cleaned it with TB cleaner and the iac valve also.
After putting things back I still have excessive idle.
At 35mph it slowly keeps accelerating. Coming to a stop, it kinda of bucks wanting to keep going until the idle drops down.
When I let my foot of the brake it wants to go by itself.
I have changed the pcv valve(ac delco) iac valve. And I believe all the vacuum hoses.
I have Been reading and searching this site and still am chasing my tail.
Please help.

 

Is this a 'W' or a 'Z' engine? The 'W' is generally CPI easily identified by the vertical throttle plate. The 'Z' is generally TBI easiy identified by the horizontal throttle plate.

In terms of either engine, ensure proper functionality of the TPS and MAF, The signal wire should read 5v.

Generally speaking the IAC should be able to be cleaned and restored to a proper functioning order, however it is not uncommon for the IAC to simply seize or have its range of motion impaired beyond cleaning. Consider replacement of the IAC and TPS. Simply cleaning the MAF in most cases will restore it to a functioning condition.

In terms of the 'W' engine only;
When you say you cleaned the throttle body, did you actually remove the upper plenum and clean the intake and throttle body? Or did you simple rotate the throttle plate and spray the visible area with throttle plate cleaner?
If you did infact remove the upper plenum before you cleaned it, did you notice any washing, or areas that appeared golden?

On either engine have you preformed a fuel pressure and leak down test? If so post your results if not do so and post your results.

Good luck report back

 

I believe you meant that the code is P0507, it makes a difference. Check out:

P0506/P0507 Explained