Need intake manifold torque specifications for 2002 Oldsmobile Alero with a 3400 engine

Check the codes. If it's the 3.4 vs then a good chance either a lower intake manifold gasket leaking or blown head gaskets as that is very common on that engine and is more noticeable in gear. Honestly hard to answer with specifics without more details including any codes stored.

Exhaust Manifold To Cylinder Head - 9.58 ft lbs
Exhaust Pipe To Exhaust Manifold - 20 ft lbs
you can check it out here, also all other torque specs for your engine.
Torque Specs Database

does it have the 3400 engine? check the oil to see if it has coolant mixing with it, they are known for bad intake manifold and head gaskets.

upper intake bolts torque is 18 ft lbs - lower intake bolts torque is 115 inch lbs.

Common engine size is the 3.4 V6 on the Alero but there was also a optional 2.4 liter I4 available. The V6 will have stamped in the engine upper intake 3400.
Thank you for using fixya and good luck.

I had a similar problem. 1999 TrailBlazer (found in books and located as an (S-10Blazer). Believe it or not the problem may be in the driver's side door. There is a motor/switch/lock part. It a "one-part" but this part has many functions. It can and will drain your battery if it isn't working properly. All doors must be shut completely.If you are having a problem with the driver's side door and the remote as I was having replacing this part will solve the problem. It isn't cheap as it has many functions. It is not just for locking and unlocking the vehicle. This solved my problem and gave me a lot of problems. Hope this helps someone.

WELL LOOK ON TOP OF INTAKE COVER IF IT SAY 2.4 YOU HAVE 4 CYLINDER IF INTAKE COVER SAY 3100 OR 3400 YOU HAVE A 6 CYLINDER ENGINE. OR LOOK AT VECHICLE VIN NUMBER 8TH NUMBER COUNTING LEFT ENGINE CODE 10TH NUMBER MODEL YEAR CODE.

3.4L Engine To Remove:

1. Remove the lower intake manifold.
2. Remove the exhaust crossover pipe.
3. If removing the right cylinder head, remove the catalytic converter from exhaust manifold.
4. If removing the left cylinder head, remove the engine oil dipstick and tube.
5. Remove the rocker arms and pushrods.
6. Remove and discard the cylinder head bolts.
7. Remove the cylinder head.
8. Clean the mating surfaces on the following items:
   • Cylinder head
   • Cylinder block
   • Intake manifold
9. Clean the cylinder block bolt threads.

NOTE: During disassembly, keep the valve train components together for proper location during assembly.
To Install:
NOTE: Coat the cylinder head bolt threads using thread sealer.

1. If removed, install the following components:
   • Exhaust manifold
   • Accessory studs
   • Spark plugs
2. Place the cylinder head gasket in position over the dowel pins. Ensure that the THIS SIDE UP note is showing.
3. Install the cylinder head. Cylinder head torque sequence ’99-‘00
   
   Cylinder head torque sequence ’01-05
   
   
4. Install the new cylinder head bolts.
   • Tighten the cylinder head bolts a first pass to 44 ft lb (60 Nm).
5. Tighten the cylinder head bolts in sequence an additional 95 degrees.
6. Install the intake gasket.
7. Install the pushrods and rocker arms.
8. Raise and support the vehicle.
9. Install the catalytic converter and dipstick tube and indicator if removed.
10. Lower the vehicle.
11. Install the exhaust crossover pipe.
12. Install the intake manifolds.
13. Connect negative battery cable.
14. Fill the cooling system.

14 ft/lbs first pass on all then an additional 30 degrees for all on final pass ..by the way 1 bolt flat to the next bolt flat is 60 degrees so all nuts get half a bolt flat final torque if ya wanna throw caution to the wind torque it to 16 ft lbs and be done with it. lol these specs are from gm ok. good luck and ps the intake pushrods are shorter than the exhaust pushrods and there is no clearance if you get them in wrong an apprentice found this out 3 years ago and a lot of people saw what happens lol..good luck

Below the intake manifold front of engine