stumbling
 

I have a 90 331 stroker. It has been doing great but about a week ago you would be driving and it would start stumbling like it is running out of gas, and a little popping and backfiring.
So I replaced the fuel filter-no change the I replaced the fuel pump-no change then I replaced the ignition modual-no change I am running out of options. I have 40lb of fuel pressure with the vacume line off the regulator at idle. This is a inerment problem it does not always run like this,but here is whats weird you can cycle the key off and back on quick asnd the stumbling goes away:mad:

Re: stumbling
 

Check all of your grounds especially the ECU ground by the battery. I would also change the ignition switch.

Re: stumbling
 

You should try pulling codes.

Re: stumbling
 

The stumbling you describe could be dozens of things.:mad:

One other item to check is the black and white fuel injector harness connectors located behind the upper intake (aka. the salt and pepper shakers). With the engine idling try wiggling them and see if you get a reaction out of the engine.

Another cause could be the return signal of one of the sensors. Try the easier stuff first.

Re: stumbling
 

I got it figured out I changed the fuel pump relay and the fuel filter.
Runs better