ddg71

I just encountered this today. I've got a 92 4Runner which has been running fine, then today on acceleration the engine will kind of chug or drop power like someones restricting fuel or jiggling the coil wire. It's not a steady on/off/on/off but it's almost like a clogged fuel filter (which is new with 1k miles on it.) but it idles fine until acceleration. Then you can't hardly get it to move. I get no check engine light or any other indicators.

Once I restart the truck it's fine again for a bit. Sometimes 10 seconds, sometimes 30+ minutes or more. It never fully stalls out, just the power falls off like it's about to stall but never does. The RPMs will hang a little too.

I've read that it's maybe a MAS issue and it needs cleaning. I don't know. I've never had any issues like this before.

I had the engine rebuilt a few years ago (12k miles on it now) by a reputable performance shop. Had the coolant sensor replaced 3 weeks ago. I put a fuel pre-filter on it years ago for sediment but that's been solved so I just leave one in place now rather than use a hose for the gap in the line. This is a major problem since I live in Atlanta and the traffic here is not friendly to broken down vehicles.

Has anyone got any thoughts or experience with this kind of issue? Any help would be greatly appreciated.

ddg71

Update:
I rented a fuel pressure tester today and it's reading within normal Toyota specs. Of course I couldn't get the truck to misbehave at all even under a pretty heavy break-torque. I don't know if I should go ahead and replace the fuel pressure regulator or not.