2.5 hanging throttle and rough idle
I've got a couple of problems that may be related, I've thrown a lot of time and nickels at this thing to no end. 94 Dakota, 2.5, 5 speed manual. I know this is the Daytona forum but there are many more Daytonas with 2.5's than Dakotas so I figured I'd have better luck here.
The two symptoms are:
Engine does not come back down to normal idle speed quickly, it hangs for a 3-4 seconds after releasing the throttle. It started doing this randomly several weeks ago.
I have a rough idle, I can hear "puffs" from the exhaust pipe at idle which seams to indicate it's a misfire. It idles smoothly after cold starts, and seems to get progressively worse as the engine warms up.
Otherwise the engine seems to run fine.
What I have done:
New injector, rebuilt throttle body, new IAC
New wires, plugs, distributor, ignition coil
Check ignition timing, 12* per FSM
New crank position sensor
New coolant temperature sensor
Checked all vacuum lines, new air filter
Checked for ODB trouble codes, none
New head gasket
New intake gasket
New o2 sensor
Unplugged the computer for 30 minutes in attempt to reset it
All to no avail. What do you guys think?