2007 V8 4Runner - Engine Quirk 2000-2500RPM

Ocean Racer · 2015-09-25T18:22:10+00:00

I have been having a problem with engine/transmission performance about a year. Only in the 2000 to 2500 rpm range does this occur. No check engine lights or codes are thrown. Been to dealer several times and they have not a clue but witness the problem. Engine bogs down or hesitates/surges only in that RPM range. Otherwise runs perfectly. Mileage seems to be going down. So far we have: Replaced Spark Plugs, Timing Belt intake clean Removed K&N intake to OEM intake Reflashed ECU several times (no Difference) Pulled the Traction Control connection (makes no difference) Has Borla Catback exhaust still installed. 2 inch leveling kit, 33.2 inch General AT2 tires, stock wheels. I am thinking it could be torque converter clutch or a Cat Convertor partly plugged up but would think it would throw a code if that was occurring. Any ideas or experience with this. Please help!