1989 Renix 4.0. Over the past few weeks I have dealt with a weird issue. All will be
 

Hello everyone,

1989 Renix 4.0. Over the past few weeks I have dealt with a weird issue. All will be fine, then randomly while driving it will start studdering/shuddering/feel like it's out of gas. At idle if the issue is present, it'll sound like it has a lope. If you put your hand under the exhaust you can feel the individual bursts of air, as opposed to a solid wave. TPS is in spec . I put a new o2 sensor in there. I thought maybe the MAP was bad. I replaced it and drove it for about 5 minutes before it came back. Replaced fuel filter, thought I fixed it because it felt good, then it came back as I pulled back into my street. The fuel coming out of my old filter was absolutely nasty, however. When the issue is present, the studdering/shuddering is most felt at maybe 1-15% throttle. That's where you can really feel it. But you can hear there's an issue and it feels like it's lacking power. Any ideas?http://tradevenue.se/


Any help will be appreciated!

good chance the fuel pump is failing.

It can be tested. Keep in mind all that crap in the fuel filter went through the pump first.

I bet that cruiser54 is correct. You can "rent" a free gauge from to test the fuel pressure from O'Reilly's. Post the results here.

Me thinks you need to pull and clean that tank BEFORE you put a new pump in it.

Yowzah!!!!!

and disconnect the fuel line in the engine bay and blow back to the fuel filter outlet. That will let you see what got past the filter and into your injectors.