I've having an issue with the engine in high rpm.Blazer 4.3,1995.

I replaced the water pump & temperature sending unit(it heating at almost 3/4 and I wanted to see if it was not the clutch switch, now I know it is $$$). Also replaced the plenum gasket.

putted back all the parts but now its revving big time. I don't have a rpm but I would say its at least 3500!

And also, I had to put a gaz hose to the tbi unit.no more gaz leak

I noticed when removing the plenum, the unit that connects in the middle of the spider is easy to remove,seems like the retainer is broken.Truck starts so I guess its ok for now.

Checked for cracks in the power brake & cruz control hose but they seem ok.

Is it air going in somewhere that I cannot seem to find? Putted some tape around the gasket to see if it sucks,but no go.

Any clue please?

Thanks in advance,

Mart

 

Sounds like it's sucking air in someplace. Take a propane torch, turn it on (don't light it ), and move it around the engine and hosing connections to see if the rpm's change while it idles. If you find a spot where it does, there's the leak.