Ive got an 86 22R with a little over 200k on it. It used to run great but recently its been running really rough...mainly at idle. It almost sounds like its loping. It doesnt stall except on cold start up, and has hesitation of the line. Here is what i have done so far.
1.cleaned the carb with some 2+2 gum cutter (with engine running)
No change
2.Pulled the plug wires to listen to change in idle.
#1 and 2 change idle drastically when pulled ie. almost stalls, while 3 and 4 dont change the idle barly at all. But when the plugwire is grounded to the valvle over it throws a strong spark. Tried swaping position of plugs, and even different plugs and wires. No change
3) Checked the float level in the carb through the looking glass and found the the fuel level is slightly high but not out of range accourding to my hanes manual.
4)Checked for vacume leaks to the best of my abilty.
found nothing
5)Did a compression check to see if a cylinder was laying down or stuck valve
compression was fine
6)Check the timming
no improvement
At this point I am confused as to if the problem is carburation or electrical
7) pulled the cap of the distributor and it looked fine. It is fairly new anyway.
The only thing that I found that seemed to throw up the red flag was that when i looked at the intake manifold there was some oil on it where is seals to the block in the back. Towards the rear two cylinders. So my theory is that maybe I have a slight induction leak, changing the mixture in the rear two cylinders causing the loping at idle???? When I spray a spall mist of 2+2 over the carb I have a slight increase in idle, which tells me that my mixture may be slightly lean.
If anyone could give me some insite as two what I can do or has any ideas please let me know. I think my next step is going to be to get a new intake gasket and throw that in.
Thanks guys and sorry for the long post. Stinson

Have to checked the intake manifold gasket?

the reason i say this is because was having same problems and i just installed a new carb, i sprayed some carb cleaner around the manifold and it rev'd up to normal idle like it's suspose to, well come to find out there was a bad leak in the intake manifold gasket.

Also your AAP on the carb might be bad...?...

You have a bad AAP diaphragm... Pull the vaccum line off of it, and sniff for fuel. If fuel is leaking into the line, the diaprragm is allowing all of that fuel to just drip down into the #1 and #2 cylinders.

Take hand held propane torch and remove burner from end of brass pipe.

Slip 24" of vac hose over brass torch pipe.

Tape free end of hose to 24" long coathanger wire.

Crack torch valve to where you hear slight hiss at end of hose, then using wire, fish hose end all around intake sealing flange....Bend wire to reach under and behind stuff.

When you get near the vac leak, the engine will smooth out.

Dirty or hanging EGR valve. With it not sealing at idle or lower RPMs it acts exactly like a vaccum leak at the intake. Clears right up once RPMs get past 2000-2500 or so.

Might try pulling it and installing a temporary block off plate between it and intake...see if that helps. If it does, pull the assembly for a thorough cleaning/possible replacement.

The part where #3 and #4 plug wires pulled doesnt effect the engine has got me really puzzled though. That would be an indication of something aint just aint right. EGR wont effect just 2 of 4 cylinders.

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />