I have an elderly friend with an 03 Quadcab with the 4.7 , 5-45 rfe transmission, optional 3.90 axle and 20&quot\\; factory wheels&amp\\;nbsp\\;with 85,000 miles on it. The guy keeps the maintenance up and doesn’t mind spending the bucks to keep his truck in TOP shape. The issue with the transmission is that after driving it on the hiway for about an hour, the transmission goes in and out of lockup with the rpms surging 3-500 rpms. He has had the fluid changed at the dealership 4 times this year alone. The dealer can’t find anything wrong and there are no codes. They have changed the filter in the transmission that looks like a small oil filter and ran a cleaner thru it in case of any valve body sticking. It still does the same thing- surging. Now the engine has started to surge at an idle. It’s surging as much as 1000 rpms but there are no codes. Anybody have any ideas on what the issue could be? The truck runs great otherwise, looks like a new one&amp\\;nbsp\\;and fuel mileage is not bad at 18-20 hiway at 70 mph. Any suggestions are appreciated.

 

You didn’t mention the other tranny filter. Assuming they changed that one, too, then maybe the throttle body needs some attention. You didn’t mention plugs and wires, either. The air filter is probably OK, but if he’s been going to the dealer for all that maintenance, it’s possible he’s paid for many things he didn’t get.

 

Yeah, all of the maintenance has been done. The dealership had been only doing a power flush every 25.000 miles but not change the pan gasket or the internal filter. Both have been done at the last fluid change about three weeks ago. Plugs, wires, and all of the stufff a dealer likes to whack you with has been done within the last 10,000 miles and the air filter about 1000 miles ago. Since there are no codes, anybody think the PCM might be going bad? I had one kinda go like this but it was on a Bronco and it was the original OBD, not the OBDII system. I would assume if the IAC was bad or malfunctioning it would code up....but no codes are showing.