So I have owned this 2000 Ford E-450 V-10 Bus for almost a year and I have slowly been working on it to make it better.

We started off by:

replacing coils, wires, and plugs
AIC
Muffler (which was blown out again by backfire)

Now im being told to either:

Replace or Clean EGR valve...

It seems to run a little rough, or not up to its V-10 potential... I am trying to get it to pass inspection but having the check engine light come on and off is not helping.

Also if anyone knows of a place to get aftermarket parts for this beast. I would like to fix it up and keep it.

 

If the check engine light is on then there are codes it's trying to tell you what is wrong with it you need to have the codes read. Auto parts stores like advanced or auto zone will read them for free or let you take the code reader out side and do it yourself. Get the codes read and post what they are This is the first step before throwing parts at it and hoping you get lucky. Any auto parts store is going to have aftermarket parts Advanced has online codes that will get you 20-30% off depending on how much you spend and what codes you use. Alot of us perfer to use Motorcraft parts over the part store brands the quality is much better and they have a 2 year unlimited mileage warranty. When it comes to plugs and coil packs you definitely want to stick with motorcraft.

 

I wanna party with you! Dang.

 

Throw a stripper pole in that and we'll all party with him!

Your engine should be OBD-I compliant which means the discount parts store's code readers won't be too helpful.

Most misfires on Modular Motors can be tracked back to the plugs, boots and sometimes COP's themselves. However if you're having backfires severe enough to blow a muffler there could be other issues perhaps as severe as camshaft timing issues.

I've personally never experienced or dealt with backfires or misses on a Modular Motor to this extent so might be way off base here. Hopefully someone with better advice will chime in and set you on a better diagnostic path.