I have a 98 blazer it started sputtering while i was driving it. does it at different speeds, cold or warmed up. I have replaced the plugs and wires, fuel filter, and even put in injector cleaner. none of this has helped(or my luck has anything to do with the problem) but it didn't hurt it, still running the same. seems to be getting worse with time. thought it was the converter because it was blowing out sooty smoke from tail pipe but that stopped. any ideas????

hold a flimsy piece of paper (dollar bill is usually used) up to the exhaust. If it gets sucked back towards the exhaust it needs a valve job.

You need to get your hands on a fuel pressure gauge somewhere. This engine uses a high pressure pump and it's very sensitive to fuel pressure.

The spec is 55 to 66PSI but it probably won't even run at 50PSI




78 Corvette Pace Car For Sale-18k mi orig-Florida

A simple misfire will give you the same result. Don't jump to a burnt valve so quickly.
Loren
SW WA

In Reply To

A misfire will create a suction in the exhaust?
How is that possible?

I'm going to quit replies to annon guests who won't sign in - so sign in!

If a valve is open the same action (of piston) that draws in air and fuel can draw from a tailpipe. That's all that means,

T
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Tom Greenleaf - MetroWest, Boston

Post deleted:

No more annon guest posts for sh*t they know little about! Sign in or get out!

T

(This post was edited by Tom Greenleaf on Sep 2, 2009, 6:06 AM)

In Reply To

That's bullSh!t Tom.

We're talking about exhaust valves. The only way that can happen is an improperly indexed cam, a valve stuck open, or a burnt valve.

It's not bull - a stuck exhaust valve knows diddle whether to take in new fuel and air or suck air from exhaust. Multiple reasons possible. You are correct but being a jerk!

Sign in or your gone!

T
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Tom Greenleaf - MetroWest, Boston

why single me out?

(edit - because you won't sign in! What's the problem?)

(This post was edited by Tom Greenleaf on Sep 3, 2009, 11:46 AM)

Sign in or I'll delete every post you make!

T
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Tom Greenleaf - MetroWest, Boston