need help on 1994 sunbird le 2.0

The car starts fine and idles good. My problem is that when it's in gear and I start to give it fuel it starts to putts and bog a little and will stall unless I put it in N or P and rev it until it stops puttsing and bogging at which point it will idle ok again. Also, If the car is in park or neutral and I rev up the engine and then let the rpms fall to idle speed then try to give it gas, the same thing will happen and it wants to stall out. I can let the car idle for an hour , or drive it and I don't get a check engine light nor is the car running hot at all, though it is running rich. The exhause color is normal, other than the smell from it running rich. I just got the car and it has new plugs and wires which I've checked over to see that they are all gapped properly and nothing is loose. This is how I could tell that it is running rich. Anyone have any thoughts or suggestions?

Was it doing it when you bought it? or did it start some time later?

Try disconnecting the battery for a few min, that'll reset the ECM. Pull the plugs, and dry them (make sure they're not fouled and are clean).

Then start from a clean slate... Make sure that the air filter is clean (clogged ones will restrict air), also... not kidding... make sure that the air INLET is not restricted... If that was sitting for a while before you bought it a Mouse could've made a home right in your air inlet (don't ask me how I know:banghead:).

If that's OK... then you could have a bad sensor (even though it's not throwing a code)... Sensors that have a say on Fuel mixture:

Oxygen sensor
Throttle Position sensor
Idle air control... not really a "sensor" but a plunger that regulates Idle fuel mixture.
Intake Air Temp. sensor
and the Manifold Absolute Pressure sensor.

But the O2 or TPS are probably the most likley culprits.

Also, Pull the EGR valve and make sure it's clean and working properly.

Or... probably the best bet (if the air inlet thing isn't it:)) is to take it to a shop and have them run a Diag. test on it... their machine should be able to read what the ECM is seeing, while taking readings from the engine itself... since you know how to cause the problem, the Diag. computer should not have a problem reading what sensor is faulty.

Then you can decide wether or not to do it yourself. Keep in mind though, that the average Diag. test ranges between $45-75... Some shops will waive that fee if you have it fixed there... but it might be money well spent considering the time it might take to pin-point the problem yourself. :2cents:

The engine only does this after it has been started for about a minute. It run fine until then.

I'd start checking your sensors then.... When you first start the engine, the ECM is not using any input from the sensors (except for the Ignition system)... it's using pre programmed settings for fuel, air, etc. Once the engine has been running for a bit, the ECM will start using the sensors readings and that's when you're having the trouble.

So, I'd say its a sensor... now you just have to find out which one. You'll need to test them to see.

Could still be the EGR... but I think its unlikley. Might want to check it anyway, as it's the easiest/cheapest thing to check first (cause it might just need to be cleaned).

A Haynes manuel will tell you how to test the sensors, it will give you the voltage and Ohm range for a properly working sensor. If you have too much or too little of either, then the ECM cannot run the engine properly.



Good Luck.