i bought a 87 trans am gta with a 350 tpi motor, bone stock with 150,000kms on it, i went through aircare and it failed, it lopes at idle and the check engine light cames on, so ichecked the code out and it gave me a lean exhaust code, i chaged the plugs, wires, cap+rotor, pcv, and air filter(a general tune up), it helped a litle, but it stil lopes at idle, i checked it out at a budys shop, he thinks it has a vacum leak through the intake manifold gasket, we did the test were u take propane torch and put it around manifold to see if afects it, but this didnt seem to detect anything?,...anyways if any of u guys could help me out that'd be great

 

What code EXACTLY is it pulling? For vacuum leaks, go in with carb cleaner and spray around. If you hear a jumpin idle speed, youve found one.

Whats your fuel pressure at?

Hows the o2 sensor/connection?

 

It's giving me a code #44 which in my manual is lean exhaust....then list a bunch of posible problems it could be...but i did try that carb cleaner trick only instead i used a propane torch, but no change in idle speed, so i couldnt defietly pin poin the leak, but the mechanic at my work says he thinks its the manifold gaske?

havent checked my fuel presure

and my O2 sensor conection looks good

 

Can you draw a voltage reading from the oxygen sensor at all?

 

havent tried that yet, but these are all hepful tips

guess tomorow i'll try to check the fuel pressure and do a 02 voltage reading..

fuel pressure suposed to 34 to 47 psi i think?
but wat should the voltage read on the 02, and how exactly do i check the 02 voltage

any other things u could think of checking? wat about the mass air flow meter...

thx cause ur input is helpful to me

 

Mass air flow: Un plug it. If the engine still runs, it isnt the problem at hand. Also, check the connections/ducting around it. Make sure it is in sound condition.

Fuel pressure: yup, that sounds about right. Test it on the schrader valve (right fuel rail). If your pressure is low, check the pump, the regulatr

O2 sensor: If yo havent replaced it in about 30,000 miles or so (48, 250ish km), you should do so. Its a good way to ensure the ECM is getting a proper signal. Connect a multi meter in parrallel to the connection that leads to the ECM. I dont have an o2 sensor so im not the most fluent with values. I think its like 250-750 or so mV with the engine hot and running.

Vacuum leaks: Did you check EVERYTHING that is vacuum operated, this includes the PCV and brake booster line.

 

ok, tomorow i check the fuel press, 02 voltage reading(I'l also try and replace), maf sensor, and im gonna do a good check of all posible vacum leaks, im gonna try to get a stethascope cause maybe that'l help find the vacum leak sound,
thx for the help i'll post back soon with some of my results

 

Cheap stethascope: get a piece of heater hose and stick it in your ear and probe around.