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88 chevy burban with a 5.7 runs rough

84CUCV

84CUCV

3/4 ton status
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new cap, wires, rotor. plugs look new so i left them. runs really rough. what would be the next steep. the gas thats in it is really old. would that do anything?

thanks
 
Must get rid of all old gas. It will run horrible with bad gas and could also cause engine failure when the valves stick open from the gummy fuel and the pistons hit them.
 
ok, how to i get it out then? best i can think in my little electric pump to get it out.
 
You are probably going to need to remove the injectors and have them professionally cleaned or install some new ones. They probably have a bunch of varnish in them from the old gas which is not allowing the injectors to have a nice conical spray pattern and possibly allowing them to drip when they should be "off".
 
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might wanna try a couple cans of Seafoam in the tank.. see if clears out those injectors some..
 
Easy test, pull and replace single plug wires while it's running, to make sure ALL of them hurt idle quality. If they don't, then there is the problem.

Don't just replace plugs (same with cap/rotor IMO) but you need to make sure they work right. Just because they look good doesn't mean they are, BTDT.
 
Been there done that. :)

Dropped some spark plugs in the box, looked fine, installed them, no workie. Porcelain had cracked below the crimp.

I figure that plugs are so easy to break (and they are, trust me) and shipping is typically so rough, the likelihood of a bad plug out of 8 is pretty good. I bought 8 autolites one time, 2 out of the 8 were bad out of the box. My Delco's have been good so far, but again, when dropped, that went out the window, and you have no idea what's happened to them up until you got your hands on them. :)
 
I don't think so. I believe someone here had mentioned being able to take them apart, but when they get cleaned, they are also tested to ensure they work correctly.

For my money, I could buy new injectors (granted, I had 8) for the cost of professional cleaning.

One of the problems with the injectors is apparently that the coils in them are coated, and if that coating starts to wear off, they go south, and nothing you can do about that. It's been awhile, but at one point I remember seeing a post (on TGO) about which injectors NOT to use injector cleaner on, as it did strip the coating. GM used at least two different designs for TPI, not sure if TBI was the same.
 
well, new gas with 2 cans of sea foam. since i was there and i had the parts. new plugs, cap, rotor, wires. found the firing order was messed up. fixed it. runs way better and smoother. started it before to move it. barely even runs. its so rough. shakes the truck. the engine light just flashes the whole time. so what am i missing. any ideas? thanks
 
If I'm reading your post right, you were able to make it run much better after your initial post (after fixing firing order) then after it was running good, it has started running bad again. Correct?

If you haven't, pull the ECM fuse out of the fuse panel for 10 seconds, (key off) replace the fuse, then start the truck. If the check engine light comes back on, check and post the code. Code pulling procedures have been posted, you might want to search "paperclip codes" or something along those lines.
 
yes that right. started running bad again. ok just need to find out witch fuse. thanks for the help
 
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