How do I replace the tps on my astro van? do i have to remove the engine cover?

Replace sensor.

two clips on floor, 15mm, and after you remove the top plastic cover on the doghouse itself, there are two 15mm bolts that go thru the firewall...will need 15mm socket and extension

You'll need to remove the interior engine cover(dog house).Torx screws for the covers, 2 bolts on floor. and bolts against the fire wall (i use a long extension with a swivel socket at the end). The IAC valve is screwed in to the side of the throttle housing (where the gas pedal hooks up to the engine).I can get a pic if you need it.

Heater Core Removal & Installation To Remove:

1. Drain the engine coolant.
2. Release and reposition the outlet heater hose clamp at the heater core.
3. Remove the outlet heater hose from the heater core.
4. Release and reposition the inlet heater hose clamp at the heater core.
5. Remove the inlet heater hose from the heater core.
6. Remove the screws that retain the cover to the heater case assembly.
7. Remove the straps that retain the heater core to the heater case assembly.
8. Remove the heater core from the vehicle.

To Install:

1. Installation is the reverse of removal.
2. Refill the cooling system.

time to buy a new van.. umm what about the alternator?

The ignition coil is mounted on the intake manifold near the distributor.
Remove the dog house, or engine cover and it will be on the right side.

Open the hood ,remove the air box for the engine but leave the mass air flow sensor on.Get some carb cleaner and spray it in the air intake tube while someone tries to start the van and if it fires and runs on the cleaner it is defanetly a fuel issue and most likely the fuel pump.If you have a fuel pressure gague you can remove the engine cover inside the van and connect to the fuel pressure port to see what u have for fuel pressure which should be between 55-65 psi to run.

What you have to do is check and see if you have fuel pressure.You have to remove the engine cover to check it.If you don`t have a pressure tester then remove the air cleaner hose to the engine and spray it with carb.cleaner or brake cleaner.If it starts for a few seconds then it is more than likely a fuel pump.If it does not start then you have to check for spark at the spark plugs.Make sure you check more than one plug.If no spark then you have to check the distributor cap and rotor.Make sure the rotor is good and cap also.Things that can cause no spark are the ignition module,coil,and cap and rotor.Hope this helps.Good luck.

check the throtle position sensor(TPS) that maybe the problem.

There are two bolts that have to be removed from under the hood with a LONG extension or sometimes a long heavy duty screwdriver.They are located towards the top of the doghouse & quite a ways back in.Good luck,
ChevRev