Hello

Today again I probed my engine with new ring, but again the Idle up and down beetewn 500 and 800 RPM aprox.

350TBI 1900 Stock, base timming at 0 degree, I cleaned IAC but the same problem.

Help me please

Saludos

i am not sure of some of your terms, but i will give it a shot. when you first start the engine does it rev up then slowly drop down. if it does not , you need a new iac control. do you have a check engine light on . has anyone moved the idle adjustment screw. there is many things that will cause this problem. can you give us more details.

I don´t have put check engine light. The problem is as you say, I start the engine does it rev up and then down (500 to 800 RPM aprox.). I don´t had moved idle asjustement screw(seal still put in TB). I saw that pintle of IAC in and out constantly to control idle. I installed other IAC of my Blazer 4.3TBI but nothing.

Saludos