Ok changed the plugs and wires. I still get a steady miss at idle. I can turn the idle mixture all the way down and the truck still runs.

The prev owner took off most of the vacume lines and the air pump. The Egr valve is still there just no vacume line to it.

I f a pull a vacum line the ilde goes up and tries to smooth out .


It has a durspark II and a Motorcraft 2150 carb. There is a vacume line from the carb to dist vacume advance but pulling the line produces no changes.

It revs up fine but steadt miss at idle.

Should I go ahead and pull the egr and block it . Or should I put the air pump back on and hook up the vacume lines where they should go.

I put a vacume gage on it at it reads between 21 -23 icnd but jumps everytime it misses.

 

It sounds like somebody has messed up your vacuum lines and emissions system without knowing what they are doing.

Get yourself a good manual and start hooking things back up like they are supposed to be.

Your carb is running on the main jets at idle which indicates real problems.

 

The vacuum gauge jumping with every miss is saying valve problems. Do a leakdown test or at least a compression test and you'll find the cylinder that isn't sealing.

 

Yes the vacume lines are a mess. The vacume canister (the famous coffie can) is hooked up in a loop with no way for it to get vacume. The are some vacume switches with nothing going to em and the lines from the can goes to two switches and back to the can.


The is a vacume line comming from the rear of the motor where the pvc and brake boster hook up going to a vacume point on the intake.

I pulled the brake line hose and thought that would kill the motor it but it kept on running . Did the same with the pvc .

I pluged the line that was going straight to the intake but it made no diff. If I unplug the line at the manifold it runs a little faster and wants to smooth out a little.

Going to get a air pump and cut the brace going to the alt bracket. The said when he disconected the air pump there was no way to tighten the alt. Works just like my inline six.

Anyway pulling the heads and sending them out couldnt hurt.

Its not a daily drive just a old flat bed 1 ton work truck I pulled two small park model mobile homes with it and it pulled them right out. The engine feels strong but has a miss.

I will get some time Sunday to go over the vacum diagram. after that off come the heads.


The I got back in my old (ragged out) 86 F150 and noticed how smooth and quite it was .

 

When you hook everything back up the M will be a lot quieter than the W because it won't be 'wheezing' anymore hehe

 

Well today I turned the idle mixture screws all the way closed. It was still running . I though maybe it was running too fast so I truned the idle speed way down untill is was just barely at an idle With Both idle mixture screws still closed.

I notice that there is a small amount of fuel leaking around the right side throttle plate shaft.

So I guess a carb rebuild or new carb is in order.

Whats a good aftermarket dist and ini setup. I can not make heads or tails of the vacume line sas the are none left that are hook up to anything. Plus most of the air pump plumbing is gone .