i recently redone my exhaust taking off clogged stock cats and old muffler with fallen baffles and none of my problems were fixed. it idles high at start up then drops down to 500rpm and when put into gear it kills sometimes. also when accelerating i hear a gurgle noise which i think is coming from the egr tube and after i turn the motor off the egr valve makes a noise for about 15-25 secs. also upon acceleration its sounds like a tapping noise from the lifters and a whining noise too. when i rev it up when its coming down it will go down to 300rpm and almost kill then pick up 500rpm and when you press the throttle a little it wants to kill then picks back up. also at start up it sounds like an explorer starting up no oil to the bearings for about a second. the truck started to never get hot so i changed the thermostat and found the old one stuck open but it still doesnt get as hot as when i first had the truck its about 1/4 way on the gauge. when driving at 45 or above when i get off the throttle all the way it sounds like its letting off alot of back pressure and acts as an exhaust break the truck slows down quick. it did this with the old exhaust too. it should return to idle rpm when letting off the throttle?? im a student tech at a ford dealer and we dont have too much material on the old sixes anymore. so far i have new fuel filter, pcv valve and breather, 2 cans of induction cleaner, motorcraft tuneup (plugs, wires, rotor/cap, w/20k on them), IAC valve. i just broke 100k and want 200k before a performance build. ive heard of injector cooling fan on these motors??? and burnt inj?!? i want to keep the truck completely legal (egr, smog pump). also i want to know of what i can do for better gas mileage and performance other than internal. should i convert to mass air?? wow i wrote alot well i hope you guys can help.

 

double check on that PCV, make sure its workin right.

Did you pick up any error codes?

 

no codes and the pcv works fine

 

Low idle says the IAC has a problem. Valve clatter is normal - mine sounds like a diesel at idle, and sometimes at speed. Revving & trans braking indicates transmission problems, common for E4OD. Do a vacuum test & a compression test.
http://www.users.bigpond.com/ergoff/vac1.htm

 

anyone else have a suggestion??