My swap is done and has been working great for about 6k miles but now something new is going on. I've driven the truck everyday to the train station to go to work. Today I tried to drive to my parents and about 30 min into the drive I started getting a rough sputtering/loss of power. After struggling to figure out what was going on, I realized that at completely open throttle (I. E. The gas pedal floored) the truck would run perfectly. Not so much at any other throttle positions. The 3.4 is out of a 99 runner. The truck is a manual. Any thought about ttroubleshooting would be great.
Thanks.

 

Maybe injectors. Fuel issue of some sort. Is it giving you a check engine light?

 

MAF dirty? Do you have a K&N? CTS faulty/unplugged.

 

Clean the MAF

 

The maf was causing a bad idle when I first did the swap so it's been off and cleaned. I would be surprised if it needs to be cleaned again, but I can check that. Oem air. Haven't done deck plate mod yet but I guess my thoughts aren't something like that since it was running just fine for a while. No cel at all. Just the horrible running problem.
I initially thought fuel problem/injectors so I put a pint of sea foam in the tank about 50 miles before I made it back home. Didn't improve at all.

What's a CTS?

 

OK. Coolant temp sensor. Just realized what you meant. I can definitely check that out. I guess I will hook up my scanner and start the truck, watching the temperature numbers on the laptop. But.... Would that give me these symptoms? I understand a rough idle coming from that but it runs so well when it's either just idling or the pedal is floored. Does this thing fail "open" or in this case at a maximum reading.

I don't know if this matters, but it had been pouring for two straight days. After I'd ran sea foam through it and kinda ruled out a fuel problem I was thinking something was getting wet or maybe the humidity was bugging something that wasn't insulated well.

I'm on my way home now and it's a dry day so my first attempt will be to see if the problem even reoccurs. I'm actually hoping it does because sorting out what's wrong won't be easy if it is only happening when it is wet out.

 

Well, a dry day and no problems with the throttle. Unfortunately. Ha! However, i put the ccomputer on the truck and got a couple of pending codes, p0172 and p1133. I know the first one is running too rich which really isn't a surprise. But the second one is something to do with the air fuel mixture sensor. The strange thing is, that a/f sensor is one of the few new parts on the whole truck. (i.e. it wasn't from the donor). So since I only have about 6000 miles on the truck since the swap, I'm lost. Any thoughts?