Both 4Runners hesitate after start.

My 1999 4cyl has a very noticeable stutter or uneven acceleration while it warms up. Not a misfire(I think). My 2001 v6 does the same thing but not as bad. I was reading another forum and a guy said that his did this and his transmission ultimately went out. Now I'm kind of scared. I haven't checked the quality of the transmission fluid recently but I am pretty sure they have plenty of it. Also, the 1999 has a check engine light that turns on and off that seems to correlate to the weird accceleration. I haven't been able to check that code since I bought it. Every time I try it clears itself before I get there. Also, the 2.7 seems to be getting around 10 miles a gallon. Are the gas tanks the same size?

 

Update. The transmission fluid is fine. Maybe a little too full. And the code is P0402. So some sort of EGR issue. Before I spend 150 dollars on a valve, does anyone have a suggestion?

 

I'm pretty new to the vehicle (3 days), but have you done a solid once over on all of the vacuum lines? My second day driving mine the tuck almost shut down at idle and I got check engine lights. Turns out I accidentally knocked off the PCV bleed line when sucking acorns out of the top of the engine. Popped the line back in and all is well with the world. This is simple I know, but vacuum leaks have created issues in the past with other cars I've owned. Check condition of lines too. If they are cracked on the underside you won't see it and it will be leaking. Actually feel the lines.

 

"P0402 - Exhaust Gas Recirculation Flow Excessive Detected"

The EGR temp sensor detected that the EGR was allowing too much exhaust into the intake. This would be like a large vacuum leak, causing motor to run rough. Check all your vacuum lines for leaks on the 2.7 first. If there is a leak that's a potential source of the problem.

 

was this ever resolved?