I have been lurking on this site researching my issues the past few days, so I thought it a good idea to sign up.

My S10 Blazer is a work only vehicle purchased 5 months ago. In the past month it has become weaker when pressing the gas pedal, knocking, stalling, etc., culminating in it not starting this past Sunday.

In looking at other threads here, I replaced the plugs, plug wires, distributor cap, and rotor last night. Now the vehicle starts and does fine at higher RPM's, but still will not idle.

The Service Engine Soon light is not on, but in checking various sensors last night, I was able to get it to come on.

Again, from other threads I have read here, I am thinking it is a vaccuum leak somewhere.

My question is, how to know where to start repalcing vaccuum lines. Has anyone had this issue and had success by replacing lines and if so, where did you find the leak?

 

Is it a TBI or CPI engine? Two things you can do. Take the IAC off and clean the air passage in the plenum. Take the EGR valve off and inspect. It could be clogged up both in the valve and the plenum. Make sure the valve can move freely. Get the gasket with the screen, if it doesn't have one. Fuel pressure checks are critical on the CPI engine. Should be 55-60 & let set for 10 mins with no more than 2psi drop. RPM should be 550-600. There is a vacuum line on the right side of the distributor that comes out of the plenum (2" steal tube) & connects into an array of more vacuum lines. These seem to pop lose more times that not....

 

It is a TBI.

When we wrapped up the other night, it was starting and running, just not idling. After a day off from working on the vehicle, we got to the vac lines last night and replaced them all one by one so as noit to make a new mess. Then, we tried to fire her up and.....nothing . Very frustrating. One step forward and wo steps back.