Check the spare tire, it has a sensor too.

Sounds like you might have worn wheel bearings.

A code P0172 may mean that one or more of the following has happened:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak.
* There could be a fuel pressure or delivery problem

Possible solutions include:

* Inspect all vacuum and PCV hoses, replace if necessary
* Cleanthe MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect fuel lines for cracks, leaks, or pinches
* Check the fuel pressure at the fuel rail
* Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
* Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

A code P0175 may mean that one or more of the following has happened:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled
* There could be a vacuum leak.
* There could be a fuel pressure or delivery problem

Possible solutions include:

* Inspect all vacuum and PCV hoses, replace if necessary
* Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect fuel lines for cracks, leaks, or pinches
* Check the fuel pressure at the fuel rail
* Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
* Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

P0700 is a pcm trouble code that basicly says there is more trouble codes in the trans controller side of the pcm. it could mean something simple like a bad speed sensor or some kinda bad like a loss of prime. gear ratio error codes can be caused by faulty sensors.

There are some other checks that might need be done, but I can tell that you just need a direction. That being said, most often, the cause of the codes P0172, P0175 are caused by a bad Downstream Oxygen (O2) Sensor so I am saying replace that and then update me. The downstream sensor is the one after the cat. The P0700 means that there is a fault code stored in the transmission control module that needs a different reader to access.

Youre welcome

Drain the coolant. Remove the thermostat housing and thermostat, located on the lower left side of the block. It may be necessary to relocate the accessories on that side to gain access. Remove the upper radiator hose from the aluminum lower intake manifold water outlet (gooseneck) on the top side of the engine. With the thermostat removed (lower left of engine) one will notice a small drilled hole, in the upper part of the cavity, about the diameter of a pencil. Use shop air and blow air into this small hole. The air should exit at the top of the engine on the left cylinder head out the lower intake water outlet (gooseneck). Use shop rags to catch debris from re-entering the cooling system. Due to the different design of the 3.5L, it may be necessary to remove the lower intake and possibly the left cylinder head to remove the debris. There is a machined pocket in the cylinder head that can trap material. Debris can be aluminum chips and casting sand. Flush the entire cooling system as well. It is likely the radiator has some debris in it as well. Try it without removing the cylinder head.

There are several places where you could have a leak in your evap control system. The purge canister, purge valve, fuel or vapor return line, tank vent line, or filler neck could all cause that code to set. Do you remember what caused the first occurance before you replaced the gas cap? Have you reset the computer (cleared the code) since installing the new cap? Was the new cap the EXACT same design as the old one?

You'll need the necessary test equipment. What is the code?

Try the AutomD Negotiator ( http://www.automd.com/negotiator/) feature on this site it is free. They will call local shops for the repair that you needed and send the multiple quotes from your local shops. So you can compare job prices within your area.

"Had hoses under van replaced, had a leak" - I doubt ths has anything to do with the rear heater not working.

Your problem sounds like the common blend door problem that got burned. The door is on a vertical axis and when it breaks, it can swing back and forth randomly giving heat or AC or nothing. The difference on acceleration is the force placed on the door swinging it one direction.

You can check the operation by fully opening the glove box, removing the actuator motor on top of the plenum box and examining the blend door axle. Pictures of the common fail signature are available on the heatertreater.net web site. There are several "free" fixes that mostly are worth what you pay for them. The solution on the web site is solid and proven over hundreds of vehicles and will resolve the problem once and for all.

http://www.300mclub.org/

try heating it up with a blow dryer

js it ok to drive when the odb lingt come on