- Joined
- August 3, 2000
- Messages
- 34,942
- Reaction score
- 11,885
- City, State
- NORTH IDAHO, 7B
- Year, Model & Trim Level
- B2 "Slightly" Modified
- Callsign
- FOURTEN
Yes I use Mobil One synthetic ATF.
Watter Wetter works great if you have heat problems, I didnt notice much change on my current setup. ON my old 2.9L it dropped my op temp by about 10 degrees.
Your thinking is correct, check the spark plugs. However you are not looking for a "bad" or "destroyed" plug. What you are looking for is a leak in your lower intake manifold. The lower intake manifold bolts come loose and the gasket leaks, causing the engine to run like crap! You need to look specifically at your #5 plug for any mis-coloration, anything other then a nice tan is bad. White = lean, black = trouble. Most Haynes manuals will have spark plug defenitions in the back.
The reason this could be causing your OD to act funny is because it can cause a major LOSS of vacuum. The OD like stated above is controlled by the computer but it also relies on the vacuum modulator on the side of the tranny, this is the vacuum line that comes up the back ofyour 4.0, is held in place by a bolt on the upper intake, and goes to the vacuum tree on the back of the intake. So if you are having rough running engine problems and shifting problems this is the best place to start.
You can fix the lower intake bolts yourself, a temporary fix is to re-torque them down in sequence, the real fix is to actually remove the upper intake, valve covers, lower intake, and replace all the gaskets. I tightened mine down about 6 months ago, took 15 minutes, I wasnt having any problems but when I checked they sure were loose, barely finger tight. they are still tight today and I plan to build a new engine soon so I dont need to replace the gaskets.
Watter Wetter works great if you have heat problems, I didnt notice much change on my current setup. ON my old 2.9L it dropped my op temp by about 10 degrees.
Your thinking is correct, check the spark plugs. However you are not looking for a "bad" or "destroyed" plug. What you are looking for is a leak in your lower intake manifold. The lower intake manifold bolts come loose and the gasket leaks, causing the engine to run like crap! You need to look specifically at your #5 plug for any mis-coloration, anything other then a nice tan is bad. White = lean, black = trouble. Most Haynes manuals will have spark plug defenitions in the back.
The reason this could be causing your OD to act funny is because it can cause a major LOSS of vacuum. The OD like stated above is controlled by the computer but it also relies on the vacuum modulator on the side of the tranny, this is the vacuum line that comes up the back ofyour 4.0, is held in place by a bolt on the upper intake, and goes to the vacuum tree on the back of the intake. So if you are having rough running engine problems and shifting problems this is the best place to start.
You can fix the lower intake bolts yourself, a temporary fix is to re-torque them down in sequence, the real fix is to actually remove the upper intake, valve covers, lower intake, and replace all the gaskets. I tightened mine down about 6 months ago, took 15 minutes, I wasnt having any problems but when I checked they sure were loose, barely finger tight. they are still tight today and I plan to build a new engine soon so I dont need to replace the gaskets.
