Chevrolet Repair: Z24 problem in motor, automatic transmission fluid, bosch spark plugs

Question
Hi,

I'm also an expert on this site...in the computer section. Let me just say thank you in advance for taking the time to answer my question.

I have a 1989 Chevrolet Cavalier Z24. The motor is a 2.8L. It's a manual transmission. In general it runs very well but my problem is the following:

Wether the vehicle is warmed up or cold, if I am idle (at a red light for example) if I press the gas to without being in gear, instead of reving higher, for a fraction of a second the odometer actually goes under 1 and it seems like the car is gasping for air then it finally revs higher, almost as if the vehicle was going to stall but it never has. Rain or shine is the same as well. In gear I did not seem to have this problem but I may have it without realizing it.

One last thing is that sometimes when it is idling, the kneedle of the odometer seems to play a little up and down. Something needs tunning and I don't know what it is

What I have done; changed the air filter, spark plugs (Bosch Platinum), wires. I have a new gas tank, gas pump, fuel filter, new exhaust system, alternator, water pump, thermostat.

I'm at a loss and don't know why the engine is weird like that.

Thank you so much for your time.
John

P.S. Could you tell me what kind of oil a manual transmission takes...no where in the manual does it says nor can anyone confirm this, they all say it depends. I can't even find where to put it!

Answer
If the fluid in the transmission is RED in color and feels much thinner than engine oil it will use Dextron II AUTOMATIC TRANSMISSION FLUID even though it IS a STANDARD SHIFT transmission.


As to your hesitation, This can be caused by:

I do NOT recommend BOSCH spark plugs in a GM engine as I have seen to many problems develop when these plugs were used. Use the AC DELCO plugs that came with the vehicle when it was built.

A blackish clored residue that has built up around and on both side of the throttle plate area and needs to be cleaned off with an aerosol type cleaning fluid that you can get in any auto parts store.

Another possibility is a fault in the EGR system.

Another could be a slight fault in the TPS (THROTTLE POSITIONING SENSOR) that may or may NOT illuminate the check engine light.


The above are the most common faults based on past experience. BUT, I really should drive the vehicle to make a more accurate diagnosis.




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