my 89 22r has a bit of a miss from idle to 2000 rpm.I dont notice it driving just sitting.It has a very slight miss at idle that gets worse up to 2000 were it smooths out.Here a list of what I have done.new ngk g power plugs,new cap and rotor,new plug wires,checked distributer pickup coil air gap,replaced carb,and the mixture srews adjusted somewere around 3-4 turns.all intake manifold and carb mounting gaskets have been replaced.checked for vacuum leaks.egr valve isnt hooked up.the only vaccum lines hooked up are to the vacuum advance,pcv valve and charcoal canisters.vacuum advance canister checks out good.the factory coil was out of spec when i tested it so im running an accel super coil.the rockers are adjusted properly.i have good compression 165-160 all around.i have good vacuum.and the timing chain has been replaced also.and it did the same thing before that carb was changed.what are the chances its the ignitor?its still the factory 1989 ignitor.Its the only thing that hasnt been messed with at this point other than blocking off the egr valve.I dont think the egr valve is sticking open but ill check . also when i changed the spark plugs they had a good brownish grey color so the a/f ratio has to be pretty good. any idea whats left to check?

 

Hmm I'd go with what your already leaning toward. If you've changed all that there ain't much left. It's gotta be a firing issue from what your explaining. Kinda sounds as if its jumping fire. But I dunno.

 

Did you check your grounding strap from firewall to head?

 

Yeah it was there when I pulled the head for head gasket job and i made sure to put it back.I also disassembled the the head and checked everything out all the valve seats looked good so it's not at burnt valve .im leaning toward an ignition problem.

 

Bump! Been too busy working to try to mess with my truck,but anyone else have any ideas?and It might also help I checked it today holding it at various rpm while in neutral and it only missed at idle -1800 rpm not 2000 as I though before

 

I had a ruff idle and a miss .Took out injectors and rebuilt them.Also cleaned throttle body and intake plenum . The EGR hole right behind the throttle body in plenum was clogged.Also changed the fuel filter while intake off a lot easier.

 

If it is has a carb sounds like a issue between the low speed jet and high. Clean the carb and check all o-rings. This wonderful fuel they give us these days is terribly hard on rubber and soft metals like jets.

 

It did it with the old carb and this one is a brand new carb .but theres always a possibility something in it but I hate to break it open.i just kinda doubt it since it did the same with the old one too

 

Did you check the firing order. I know this sounds stupid and obvious but I once replaced the fuel injectors in a s-10 I had just to find out I kicked a fuse. I would go over everything from the fuel cap all the way to the cat.

 

I would go back to stock coil, re-do timing, adjust idle mixture, re-time motor again. However, nothing is going to work properly if your vacuum lines are crossed and or not hooked up right.

 

Thanks for the suggestions. Goin to try to figure it out tomorrow. Vacuum lines are hooked up correct. and the firing order is correct.i wish I had a throttle body and injectors to clean. Lol but mines a carburetor .I'm still leaning toward an ignition problem.but before I changed the plugs and wires , ignition coil and the carb it had the same problem.i didn't change all the parts due to this problem like it sounds though.i still wonder if its the igniter it's the only thing that hasn't been replaced and I can't find anywhere how to test it.i might just do a temp Chevy ignition module conversion Since I have an old Chevy and always have a spare laying around before I spend the money to buy another one

 

Silly Question but is the choke opening all the way? I had the same problem and went tho 100$ in parts and a lot of time just to find out that my brand new Weber carb's electric choke was defective and not opening all the way.

 

Thanks for suggestion but I adjusted the choke per factory service manual a week ago just to make sure it was good