4Runner cuts out when going down the freeway

[Cruiserhiggs]

ok guys this one has me stumped. i have a 88 runner with a v6. I drove from phoenix to las vegas without any problems till i got to vegas and my truck started cutting out while diving down the freeway. so i decided to change the fuel filter. drove it around vegas no problems at all. when i was headed home i got around 60 miles out of vegas and it started cutting out again. it feels like its chugging. like someone turned it off and then right back on. the more throttle i give it the worse it gets. i can pull over and let it idle or turn it off for 5 minutes and then i can go again and it wont do it again for like 15 miles so it sounds heat related. anyone got any ideas?

 

[pappy]

Fuel pump? Does it buck hard, or does the power "flow" in and out.

 

["N8"]

can you drive it smoothly at slow speeds. (more importantly at low throttle input will it drive)

???

 

[Cruiserhiggs]

Fuel pump is only a couple months old and it bucks hard. Yeah if i don't give it more than 1/4 throttle it is fine.

 

["N8"]

well that sounds suspiciously like a fuel delivery problem. I guess its possible the tps could be doing this to you but not ultra likely i wouldnt think. check the ecu codes and see if any tps or o2/mass air stuff comes up. but I would really be rechecking all the power conections to the fuel sending unit and make sure your fuel lines arnt leaking bent or kinked.

 

[Cruiserhiggs]

yeah i thought fuel delivery too but the thing that stumped me was it ran fine till i got to vegas and runs fine around town. it doesn't start acting up till i drive ant high speeds for a long period of time.

 

["N8"]

thats precicely why I think fuel delivery. It sounds like only a percentage of what the engine needs is getting to it, and when it asks for more fuel its getting starved. its pretty hard to do but make sure youve got the fuel filter installed in the right direction, and check the sending unit is working properly.

 

[2ndGenToyotaFan]

Maybe a failing pressure regulator is giving you too low of fuel pressure?

 

[ms018kmf]

Regarding fuel delivery what shape is your VAF in?

I had intermittent problems with stumbles but nothing was consistent. Finally after having the truck down a couple of weeks for fab work it would barely idle. After checking the usual hoses and such I found my VAF's trap door was seized up. I took it apart as far as I needed to to flush out the hinge pin with mineral spirits, carefully avoiding the electronics.

It runs better than ever now, I think my failed water crossing has something to do with this. Just another thought on fuel delivery, good luck!