My '85 22R has been running pretty bad lately. It starts right up, idles fine, and actually runs, but when I get on the gas, it starts sputtering really bad and has even back-fired a time or two. Initially, I thought that maybe the fuel filter was clogged, so I replaced that, no change. So I did a tune-up; cap, rotor, wires, plugs, air filter, timing, etc, but still have the same problems. Any advice?

Symptoms; engine sounds like it's going to cut out anywhere beyond half throttle. It will stay running, but sputters violently.

I'm suspecting a carb problem or fuel pump, but won't rule anything out at this point.

I've got an 80 that's doing the same. I've replaced the fuel filter, fuel pump and still runs the same. Except now it'll only start if I pour gas in the carb. and then it dies, no fuel?????

is that and electruic punp or manual (never had a carbed truck before) if it is i would suspect that to

How about taking the EGR off and giving it a good scrub? Also I'd check for a vacuum leak, maybe just throw some new vac lines on it for the hell of it.

Manual pump.

yup, thats your carb acting up.

Is there any difference when its cold/warmed up? Check your choke. The passenger side choke plate should be about 1/8" open before you start it for the day after you have floored the pedal ONCE. Flooring the pedal engages the choke when cold. When the engine warms, the pass side choke plate should open completely. The drivers side plate does its own thing by vacum, dont worry about it.

IF chokes working properly.. then a jet or two could be clogged. For starters, try spraying much carb cleaner down your intake while someone revs the engine. Since you say it happens when you are at full throttle, try to spray when at WOT. If that doesn't help, try taking the top off the carb, and spraying each jet individually wiht carb cleaner/hose at end of spray bottle. Then just spray a ton in the bowl,, try and get it 50/50 gas/cleaner in the bowl. Let sit for 20min. If your lucky whatever is clogged will declog. If not, its probably time for a rebuild, in which case I can give you more info on that.

So, 1, check choke. 2, clean out carb nicen good. You started in the right place with the tuneup <img src="/forums/images/graemlins/kewl.gif" alt="" /> now gotta dig a little deeper.

Good luck, and ask any more questions you might have.

-Scerb

To add, AAP diagphram; inboard side, 3 screws. Easy to replace. This is a common carb wear item. If you have sooty exhaust and soot in the carb, change it.

Fuel pump would be next; they don't go bad often, but they do.

Also check the site glass BEFORE you start the truck for the day; the fuel level should be at the midpoint.

Well Scerb, my choke doesn't work then , it stays open. It hasn't run long enough to get warmed up lately.

Well, if your passenger side choke plate isn't closing at all when cold, then that will certainly create the problem you describe.

When the engine is completely cooled down, floor the pedal to engage the choke. Try loosening the choke housing cover.. if your lucky you have screws on the choke cap not rivets. Don't pull the cover off yet, just loosen the screws enough so you can rotate it. Rotate the cover until the passenger choke plate is 1/8" open (mostly shut). Tighten down cover and see if problem goes away. Make sure the palte still opens up when the engine warms.

See how that goes..

Scerb

Does anyone know if there is a part number for just the AAP diaphragm? like at autozone or checkers? my truck won't idle and is also missing mostly a or slightly above idle. I haven't changed anything, sound like an AAP?