...........what are the correct plugs for a year 2000 4.3 blazer? i believe its the sigle point injection model. do you need the platinum ones?
also, what is the correct idle speed? mine idles at 500 rpm which seems a little slow.

mick.

 

The correct plugs are double platinums. I would go with either AC Delco or NGK as these were both used as original equipment.

Idle speed is controlled by the PCM by adjusting the IAC (idle air control) valve in and out. This valve is located in the throttle body and controls air flow through a passage allowing it to bypass the main throttle blade.

When you say that it idles at 500RPM, is this fully warmed up or cold, in gear or in park/neutral?

 

thank you for the reply.
the plugs are as i expected, but i think i have got away with changing them, fornow. the stuttering was due to a loose HT lead. and once plugged back in properly now runs smooth.
as for the idle speed, it is 550 rpm, when in neutral and engine warmed up to full operating tempreture. this to me seems 100 rpm or so too low. but you guys are the experts, what do you think?

regards,
mick.

 

Sounds fine to me. Do you get any hesitation when you take off from a stop? Does it feel like it wants to die when you are in gear? If not, then it is operating as it should.

BTW, what is an "HT lead"? I think you are talking about the battery connection...

 

over here we call the plug lead side of the distributor the LT(low tension) side. and the main lead into the distributor the HT(high tension). referring to the lower and higher voltage.

mick.

 

Ah ok. I did a quick google search, but it did not list specifics.

These plug wires have a tendency to work themselves off. What happens is air gets trapped inside the boot and as the air heats up and expands, it pushes the boot off enough to disconnect the conductors. Using dielectric grease makes this worse as it is a means of lubrication which aids this affect. I use a small screw driver in the end of the boot as I slide it over the tower on the distributor to allow the air to escape.

 

Never heard of NGK plugs being original. Guess you learn something every day.

 

I have seen it both ways. AC Delco and NGK. I have found no rhyme or reason to it.