perushing

I have an '87 Toyota Pickup. A 22R 4-cylinder engine.

My situation is this:

My truck has no problems starting and runs great at idle. It drives good until I get towards the top of 3rd gear. When I try to accelerate my truck stutters and shakes until I let off the gas. It does it especially when I'm going up hills or putting any kind of load on.

Normally my engine is very loud when I accelerate and when this happens, my engine sounds very muffled and has very little if any power.

I suspect my carburetor needs to be more finely tuned, but I have messed with my timing and mixture until it sounds like it runs well, but it still doesn't affect how it drives.

Another thing I should add is that this doesn't happen all the time. Sometimes my truck runs great, but the majority of the time I have the stuttering issue.

Please help!

gofar22r

check your gas level sound like your starven but efi would fix it. cheap to change and the biggest hp upgrade you'll get out of it :]

perushing

Sorry I'm not quite sure what you're saying. Can you be more specific please?

Sensei

He's suggesting you swap in a fuel injection system ( EFI) to eliminate your problem. Your vehicle is basically running out of fuel in your upper rpm bands. The tuning you mentioned was all done on the idle circuit. When you come off idle you start pulling through the main jets which is a different fuel circuit in your carb.
Sounds like you are running lean which means not enough fuel. Check your float level to ensure proper fuel level in your float bowl.
Run a plug check. Run in second or third gear down a roadway until it starts sputtering. Immediately shut off the engine, pull over, and pull a spark plug. If the ceramic around the tip is colored grey to white then your engine is running lean. If the ceramic is tan to dark brown then the issue is somewhere else.
Let us know....

mightymouse

iTrader: (6)

Start with the small stuff first. Check your plugs, wires, rotor, cap, all the basic things to eliminate the obvious stuff. (trust me i've been there it always has the possibilty of being the obvious stuff). Do some searching as i think there was a thread on this earlier this week. Simple things like a bad tank of gas to bad spark plugs can do this. A clogged air filter might be the problem as well.
Not that the efi swap is a bad idea (actually a good one for certain cases) but it's kinda like what the sas guys tell the ifs wheelers "why don't you just sas it". An efi swap isn't a universal cure all for carb problems. It would be smarter and probably cheaper to actually find, figure out, and fix the problem.

83

EFI also isn't easy or cheap, unless you really know your way around your engine & electrical systems. Definitely replace your fuel filter. It's just so cheap and easy, and it probably needs it anyways. From there, yeah, air filter, and then learn your carb. This is a good start, along with an FSM : http://www.bluebassdesign.com/boonin/carb_faq/

xxxtreme22r

My money is on the fuel filter or fuel pump.

If one day it runs fine and all of a sudden it acts up, DO NOT adjust the idle mix screw it's not your problem. Especially if you don't know what you are doing.

Yes a tired old engine could benefit from some turning of the idle mix screw but if all of a sudden it starts to act up, it's not what is causing it. I have seen too many people mess with that thing and screw stuff up worse then when they went in to fix the original problem.

A bad air filter will not cause your problems unless you dunked the engine into so nasty water/mud. Air filters just don't fail all of a sudden.

A fuel filter and fuel pump however can. Since these fuel pumps also have an integrated fuel pressure regulator that is usually where the problem lies in upper rpm fuel supply. If you have a hard time starting after a long period of time, I would look into the fuel filter as well. But it certainly wouldn't hurt to replace it anyway as it's cheap.

perushing

Okay, I just changed the air filter like 2 weeks ago. My mixture screw is back where it started from. My dad and I used a carb kit and replaced a lot of the diaphragms and other things inside the carb about 8 months ago. I just bought a fuel filter about an hour ago and I'm going to change it here shortly. My plugs and wires have already been checked out along with the cap. And about a year ago my dad and I rebuilt my engine and put in a new fuel pump. I'm leaning more towards it being the fuel filter is clogged up or something because if it were the fuel pump, I find it unlikely that sometimes it runs like nothing is wrong and then the majority it has the issues already mentioned. I will let you guys know what happens after I change my fuel filter.

Thanks for the help everyone, I will keep you all posted.

83

You have the mechanical fuel pump bolted to the side of the engine, correct?

Yeah, let us know what happens after the fuel filter change.

perushing

I changed the fuel filter yesterday and then drove to work and home, and then drove it again today and everything was much better. It was running like a champ again. I'm going to drive it for a few more days and see if it sputters again, but hopefully it was only the fuel filter because that was an easy fix.

And yes 83, I have the mechanical fuel pump bolter to the side of the engine.

EDIT: I just emptied out what gas was in the old fuel filter and out of one side it ran out clean and the other side was all murky and muddy-looking. I think that was my problem. Once again, gonna see how it drives for the next few days.