My boyfriend owns a '95 3VZE... it recently developed an interesting habit while driving.

The truck starts absolutely fine. But, it will chug on acceleration (full car movement, rpms dropping and shooting up, minor light dimming - a feeling like the truck really wants to die out), and attempt to even out. On a downshift with the rpms rising nothing occurs. The truck WILL NOT STALL. It will just chug/buck and sort of even out after a short period of time.
**/it will NOT do this at an idle whatsoever.

It will do this right after starting, and sometimes wont bother to do it at all -not consistent whatsoever. It will chug/buck for 30 seconds, on and off for a few minutes and then not do it again all night, sometimes we go a whole night where it does absolutely nothing. But it has become much more frequent in the last week...

* When it occurs, sometimes the battery light comes on slightly and goes off right away?

I've pointed out his idle seems to sit a bit low, and that he el desparado needs an oil change, other than such though the vehicle drives just fine...

Any ideas???

 

Symptoms point to two possibilities in my knowledge base, which others may disagree with. The two possible suspects would be the fuel pressure regulator, and the fuel filter itself. The battery indicator would be a side effect from rpms dropping low enough that the low end diode is no longer supplying voltage. Less likely cadidates are the egr being possibly clogged, or a vaccuum leak. I am sure others will chime in, but I would check the usual suspects first. A proper tune up is never a bad idea.

 

vacuum leak... somewhere

 

^X2 on the fuel filter. PITA to change.

 

Also, check for loose or corroded wires both 12v and ground.
Going bad/dirty fuel injector.