5.0hh no misfiring :(

A little more info would be helpfull. Fuel injected? Carbureted? Is it in a mustang or a tiger? The more information the better.

Whats your base timing set at?? What your base fuel pressure set at?? Are the spark plugs new with the new install?? Even though it may seem stupid every small detail helps. Maybe raising the base idle and some minor adjustments will smooth it out.

What about firing order? You are using 302 ho firing order. When you installed the heads was #1 pistion at TDC?? When at TDC balancer ponter at 0*? I have seen cars run poorly but run at 180*. Does it backfire or pop??

Have you tried advancing the timing to get any different results??

Try advancing the car only when idling. When you advance or retard the timing you will feel the car change its idle quality. Put a timing light on it and try 3 or 4* and see what happens. Detenation sounds like a tin can with marbles shaking violently. You should be alright until WOT blasts. Advance the timing to 14* base with spout out, and rev the motor. How is the throttle response as it sits?? When you give it gas does it want to die??

Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a
jumper wire or paper clip to put the computer into test mode. Start
the engine and let it go through the normal diagnostic tests, then
quickly press the throttle to the floor. The engine RPM should exceed
2500 RPM's for a brief second. The engine RPM's will increase to about
1450-1600 RPM and hold steady. The engine will shut off power to each
injector, one at a time. When it has sequenced through all 8 injectors,
it will flash 9 for everything OK, or the number of the failing cylinder
such as 2 for cylinder #2. Quickly pressing the throttle again up to
2500 RPM’s will cause the test to re-run with smaller qualifying figures.
Do it a third time, and if the same cylinder shows up, the cylinder is
weak and isn’t putting out power like it should. See the Chilton’s Shop
manual for the complete test procedure

Here's the link to dump the computer codes with only a jumper wire
or paper clip and the check engine light, or test light or voltmeter.
I’ve used it for years, and it works great.



See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

For those who are intimidated by all the wires & connections,
see http://www.actron.com/product_detail.php?pid=16153 for what a
typical hand scanner looks like. Normal retail price is about $30 or so
at Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx –
It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder
balance test. Low compression on one of these cylinders rules out the
injectors as being the most likely cause of the problem. Look at cylinders
that fail the cylinder balance test but have good compression. These
cylinders either have a bad injector, bad spark plug or spark plug wire.
Move the wire and then the spark plug to another cylinder and run the
cylinder balance test again. If it follows the moved wire or spark plug,
you have found the problem. If the same cylinder fails the test again,
the injector is bad. If different cylinders fail the cylinder balance test,
you have ignition problems or wiring problems in the 10 pin black &
white electrical connectors located by the EGR.

How to do a compression test:
Only use a compression tester with a screw in adapter for the spark
plug hole. The other type leaks too much to get an accurate reading.
Your local auto parts store may have a compression tester to rent.
If you do mechanic work on your own car on a regular basis, it would
be a good tool to add to your collection.

With the engine warmed up, remove all spark plugs and prop the
throttle wide open, crank the engine until it the gage reading stops
increasing. On a cold engine, it will be hard to tell what's good &
what's not. Some of the recent posts have numbers ranging from
140-170 psi. If the compression is low, squirt some oil in the cylinder
and do it again – if it comes up, the rings are worn. There should be
no more than 10% difference between cylinders. Use a blow down
leak test (puts compressed air inside cylinders) on cylinders that
have more than 10% difference.

Just wondering, What spark plugs are you using?

Also if you need to check for fuel you can use one of those little lights they sell at autozone or whatever that tests for power and pulse at the injector plug. At least that would rule out the harness side of fuel.

The cylender balance test as well as pulling the codes is a good place to start.

You know I went through that one time. Turned out I ran the cylinder balance test and I had swapped spark plug wires on the 2 and 3 cylinders. DUH!!! but it was definitely a good idea when my car was missing

Have you done the cylinder balance test yet? What were the results?

All the directions are in my first post. I suggest that you go back and carefully read it again.