Ok, I have a 88 Camaro 305 TBI, I have this problem, it shakes like out of time, stalls while hard braking, idles rough, seems to smell like fuel bad when under the hood. I am getting no sensor codes.

I have replaced items due to codes and suggestions, it still seems to run the same way, please help im confused, and my local mechanic is lost as well, I dont have the extra cash to take it to a dealer garage for repairs.

I have added this new, O2 Sensor, Throttle postiion sensor( I have correct voltage, tested it today) , MAP sensor, Coolant Sensor(sensor on front of block in the middle), Idle Control Sensor, New Plugs and wires, Had it timed with a light, cleaned throttle body, replaced throttle body gasket, checked vacuum lines,guess they are correct from what I can tell,any more tips or help? thanks Scott

 

Was it timed properly? The timing control connector from the ECM must be disconnected if not, you will be running between 25 and 28* retarded on your initial timing. Another thing to check would be your fuel pressure. Once you get below 9lbs of pressure, drivability, performance, and starting (hot or cold) starts to suffer.
If you check and the pressure is within the 9-13 lb range, perhaps a minute adj. of the throttle stop screw (used to be called idle adj. screw) might help. It might have a cap over the hole on the front of the TB that you can remove and I think the screw adjusts with a torx wrench. I wouldn't adj. it more than a half turn though, just enough to compensate for wear that may have occured from high milage. Be sure to examine the external coil wires and make sure their not arcing on each other or anything else. I've had that happen and it causes a stumble and makes the tach needle bounce around. good luck!

 

Thanks a lot, I had them check the fuel pressure and they said it was fine, but it was checked from the back right past the fuel filter, should i take another reading? up closer to the tbi?
also my tach needle does bounce all around, untill i floor it then it seems to work

 

No need to re-check, they probably installed the gauge between the filter and the TBI. Be sure to check the wires going to your coil and separate them and be sure they aren't touching the air cleaner when you put it back on.

 

After you get off idle and give it gas does it run OK. If it runs OK after say 35mph or so suspect an EGR problem. EGR will cause rough idle and stalling if for some reason it is stuck open. Many times they just get carboned up and they won't close allowing exhaust gas into the engine at low rpm causing your problem. Also, use the vacuum diagram and check all vacuum lines for leaks.

 

A bouncing tach is typcially caused by an ignition problem. Could any any component in the system: wires, coil, cap, rotor, pickup coil, ignition module, plugs. . .

RBob.

 

Thanks a lot all who answered, ok another question, where do I find a vacuum diagram? I have a Hanynes manual and a chilton manual and neither one have my Vin which is E or the year schematic of the vacuum system, any tips where I may find one, Thanks

 

Sticker under the hood. Not even the factory service manual (Helm) has vacuum diagrams.

Maybe someone can take a picture of theirs and post it. . .

Can also inquire on the TBI board.

RBob.

 

The Chilton manual has all vacuum diagrams in the emission section.