ok heres the deal,ive replaced the cap and button,wires and plugs,coil,ignition module,replaced the fuel filter had the fuel injectors cleaned,timing set,mass air cleaned and my car still has a miss in it.the car sets and idles fine ,if you hold the gas at a steady position,it misses pretty bad but if you mash the gas,it still misses but not as bad,seems to miss more when you have a load on the car. what could this problem be,and how to fix
my car just started doing this all of a sudden :bang:

 

How many miles on the engine? I had a similar problem once and cthe cause was the distributor shaft was worn, causing the timing to vary under load and the car to miss. Of course, my 5.0 had 200K on it, if yours has less, it might not be the problem. Wish I could be of greater assistance.

 

Just a guess but I am thinking vacuum leak.
Is it an automatic?
If yes? there is a vacuum line that goes down to the side of the tranny check to see if it has cracks.

You can also remove from the tranny for a second a see if any red tranny fluid is being sucked up the tube?
If yes than you need a vacuum modulater about 14 bucks I think. And do this with the engine cold so you don't get burned by the exhaust.

Lets see ways to check for vacuum leaks?
Some people will use a hollow tube in much the same way a Dr. use's a stethscope. Listen for a hissing sound with the engine running. Be very care of the moving parts on motor.

Another way to leak test is to use an un lit propane torch.
With the car running you spray various hose areas with the air like gas. Listen to the engines RPM as you do this.
If the RPM raises in only certain areas you will than find the leak. Hope this helps be very careful.

 

my cars plug wires are still arcing with each other and the a/c metal lines,this makes the 3rd set.
so i guess why am i getting arc with the wires,2 sets were autolites and the last set wich are still on the car are accel,i put them on today
and my car has 140,000 miles.