montana_28

Hey all... new here!

So here's the issue... I have a 96 GMC Suburban with the 5.7L 350 EFI motor that started running like crap all of a sudden. It starts just fine, but idles either very rough or very high... it also over night developed a serious spark knock when under minimal load, but gets much more noticeable during acceleration. I tried an injector cleaner/ cylinder cleaner with no change. At this point, I am leaning more towards the knock sensor. My theory is that it retarded/advanced the timing and then puked. I am mechanically inclined, but not a professional by any stretch. I feel a bit stupid at this point, mainly because I can't even seem to locate the thing and my Chilton's isn't much help with that. Any help and or ideas would be GREATLY APPRECIATED!!!!

Thanks in advance!!

MT

maxxman04

pull egr and clean it. should be located at front of engine, next to the thermostat housing. this can get clogged with carbon and cause problems. it's also highly recommended to go buy a new egr gasket that has the screen in it. this gasket will help keep carbon out of valve.

PastorK

I think I need to do the same with my 96, but stupid question, how do clean it? If I remove it, does anything come out? I'm assuming from what I read it's just exhaust gasses and not any fluid of any type?

I'm tired of mine running like crap too.

maxxman04

carb cleaner, brake cleaner, something like that works fine. no liquids. black, sooty carbon, maybe even carbon chunks. clean em out, call it good

BARTS4X4

i soaked mine in break clean. and then poked the valve to make sure it was working fine.

cam3439

I used a good strong carb cleaner to clean the egr. While you're doing this I would also clean the iac. The iac controls the idle. I used a tooth brush to clean out the IAC from all the carbon build up along with the carb cleaner. My idle was fine, but my throttle response increase by a noticeable amount.

PastorK

I just pulled mine off and there was NO gasket under it. The "valve" will move up and down if I push it with a pencil. A little black in there, but didn't look too bad.

Think the missing gasket could be part of my problem? Going to go get one right now.

PastorK

Cleaned the EGR with Carb Cleaner, as well as installed a new gasket. Started right up, and now idles at 700-800rmp (was idleing at 1000-1200 before), and the hesitation and almost dying when pushing the gas is completely gone. Took it out for a test drive. Streets are a little damp right now. I made a very slow u turn and hit the gas and got the burb sideways and then straight down the road. Before, it would have tried to die and then have to think about actually moving.

Thank you all for the help!!!

maxxman04

glad she runs good for ya!