Engine Hesitation. HELP!!!!

ok..my 91 b2600i is running like crap. it will idle just fine but then when im driving, and accelorating, it stumbles and acts like its not getting fuel. My timing is spot on and i dont have any miss fires. It has a brand new fuel filter and my fuel pump seems to be opperting just fine..The ignition coil is also fine.. I just dont understand what the problem it. PLEASE HELP.

Well, it isn't your fuel filter, coil, or any other thing. What it probably is your igniter in your distributer. What happens is that at idle it runs fine however when your voltage increases the temp increases and it starts to overheat, then igniter starts to shut down. Which in returns gives you sporadic spark. Giving the appearance that your timing is off or that you are running out of fuel. So that is a easy fix, you just need replace the igniter however in Mazda's you cant just replace the igniter like you could in chevy or a ford. Ford and chevy have the same thing however they call it a magnetic pickup. So what I would do is buy a used distributor from like a junkyard or buy one from ebay. You can probably find one cheaper by searching on the internet on A1 cardone distributors. I hope that helps.

2600i's also have a problem at about 100,000 miles with their computer.One of the components leaks an acid compound and burns a hole in the motherboard,causing poor performance especially when hot.U can pull the computer and inspect the board and if bad u can see a small burn spot on the board.Guy down in Florida fixes them for a 100 bucks or so-advertizes on eBay.BJ

My truck did the same thing when the fuel pump was dying. But check the computer first thats the cause of most of the problems for these trucks.

I forgot to mention that I already swapped the computer with the one from my parts truck. But my parts truck had 324,000 miles on it..So the chances of that being bad are still pretty high huh?

Check out your cat...a while back mine was almost completly plugged and it made it run like crap, it would idle fine but under accereration it would sputter and not rev. up...replaced it and the problem was fixed

One other suggestion-take the small rubber hose off ur throttle body and spray some cleaner into ur throttle body(put a rag under the throttle so that the cleaner wont drip on wiring).May be ur throttle plate is gunked up and ur injectors.That might clean things out a bit.BJ