Poor running 92 Suburban

Could your fuel pump have gone bad. Is it a throttle body or Multi Port.

vacuum leak.

Check the bolts on the throttle body, make sure it is tight to the intake manifold. Also check all of the vacuum lines and make sure the EGR valve is not leaking.

good luck, mark

It's a TBI, and I'd check the fuel filter first.

Doc

Doubt it; vacuum leak would be consistent the whole time he's driving, not intermittant.

Doc

Doc, I have changed the fuel filter on it, I forgot to mention that on my original post.

had similar symptoms in a 93 S-10 4.3

needed a fuel pump

Ok, I had a similar problem in my suburban and the dealer replaced the tbi to manifold gasket. They said they thought it was sealing when it warmed up and when cold everything contracted breaking the seal...this was on a 91 which should be the exact drivetrain. Thanks for the help I appreciate it. :-)

mark

I was just about to say it's time to run a line pressure test on the fuel system. Damn TBI's don't have a Schraeder valve anywhere in the system so you'll have to adapt off a line somewhere if you choose to test it at all. If it's more than 10 years old (the fuel pump) I'd replace it anyways as it'll be puking out sooner or later.

Doc

quick test: take one of those 'heater hose clamp-off' type vice grips and clamp down on the return line while watching the O2 sensor readings and injector pulse width on a scan tool

you will see (at idle) the IPW return to around 1.2 mS and O2 go from 'lean' to switching back and forth from rich to lean if the pump is on its way out

I filed that message for a rainy day G, thanks. Beats the shit outta adapting the damn line to get a pressure guage in there.................

Doc

Well, I am going to change the fuel pump tonight, I will post results when done, thanks everyone for your input.

Well I changed the fuel pump and that fixed it, runs like a new one now. I was really dreading the job but it wasn't that bad, 2 hours and I was done. Thanks for everyone's help.

Good for you. You dropped the tank and reinstall everything in 2 hrs.?. I am impressed. :-)

mark

Must not have gotten into the beers whilst working on it eh? A 2 hour job usually takes me 4-5 due to numerous beer breaks............

Doc

I always try and finish the job first then double up on the beer to make up for lost time. Yep, the tank was empty, in fact I ran out of gas on my way to the shop where I worked on it, a friend of mine has a nice shop with a lift so that made the job much easier.

I'll drink Mr. Beam or some Glen Fiddich during the colder months, but if it's over 50* outside it's beer time! My buddy is trying to sell me his old kegorator for my garage so we can have brews on tap whilst working; if that happens I'll never get anything done.

Doc