So I've had my 90 4Runner for many years now, in the pass year it blew a head gasket. With 270k miles on it I decided to get a JDM engine. A 95 4Runner engine with 30k miles on it. I have a buddy who is a mechanic and very helpful, just at times I need help he's hard to get a hold of. I'm coming here for help.

Anyways, the problem is whenever the truck has been sitting there long enough for it to cool down, it takes quite a bit of time to warm it up. At times I'll let it warm up for a good 20mins and it will run fine. If I'm in a hurry and go after its been running for 5mins or so, whenever I hit the accelerator the RPMs drop and it fails to go for a second then accelerates. Could that be due to the BVSV? It was broken during the swap and right now only has one hose going to it from the throttle body. Sure is a hard piece to get a hold of, if you don't go through Toyota. I pulled out the Thermostat and it seemed fine, even though I have no idea what one is like that is failing.
Doesn't seem right that it would take that long to warm up.

Oh, and this is one of many other problems, so those who know a lot please look for future posts.

If anyone could help that would be wonderful. I really love my truck and would love to get all the little problems fix before I start modifying it.
Thanks.

 

Easy enough to test the thermostat. Drop it in a pot of hot water on the stove, stick in a candy thermometer and put the heat to the pot. Watch for the temp. the t-stat starts to open and when it fully opens. See how that jives with the temp. rating stamped on the unit. Stock should be around 190F/88C:
- http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

Might be it has too cool a t-stat (like 160-180F) or the t-stat may not be closing fully or someone may have drilled out the flange with too large a bypass hole.