It starts fine but it misses when it is started we changed plugs n wires and egr valve. could it be the timing?

interesting, ricky ? could b anything. fuel filter needs changed, the fuel we use today is garbage, ethanol is bad for our older engines. add some of that new dirt to tank, something360. ??? also, maybe a wire connection is loose., or bad spark plug wires? something is missing its continuity , making the engine miss, not your transmission, u hope ? start with checking your battery conn., clean, tight, etc., replace plug wires, change spark plugs, maybe ? but your plug wires could b the problem. ??? think about it, engine starts ok, its when its running does the problem come up. you have fuel, you need spark, you also need clean air .......... change air filter....... pcv valve......egr valve ?? could b sticking ......you treat yourself good, yes? treat your engine good...whens last time the transmission fluid and filter was changed ??? that could also cause a miss, a surge......yes? i hope this helps you ricky, just use common sence, it always serves me well, good luck, ken

you could have a sticky EGR valve, also the ign module could be going bad

Try changing the fuel filter.the fuel pump may be going bad also. Is the check engine light on?

Hello: You might check the dist cap and rotor for white powder corrosion. Check the spark plug wires. Make sure wires are not against metal. If you load up the truck does it miss?

start with simple tune up plugs and plug wires and cap and rotor if it still misses check egr valve and exhaust sensors make sure it exhuasting right

Try running injector cleaner like Lucas injector cleaner through the fuel system and also check the fuel pressure regulator. If the fuel pressure regulator is bad or the vacuum hose has a leak, that's where the problem may be. The other to is to try and clean out your EGR valve. A dirty or stuck EGR valve will give you the problems your described, Remove the EGR valve and clean it out with carb cleaner and make sure that the valve is not seized and can move. Good luck and hope this helps. Keep me posted, be glad to get your car running 100% again.

The po301 is a misfire code. The backfire can be caused by a excessive amount of fuel, bad valve timing etc.
My guess is you have damage to an exhaust valve that may have occurred when you had the timing belt problem.A compression test will indicate if you have a leaking exhaust valve.The reason for the backfire is the exhaust valve is still partially open when the spark plug fires.

Pin point the dead hole and check that injector.

Hi,you can re check timing, run compression test,

try a compression test on that cylinder, sounds like you might have a valve problem