Allrighty guys I'm stumped and thus asking for help. I have an '89 305 TBI firebird what was originally an auto, that I swapped over to manual. (Which I do no tknow if is relevant).

While driving the car, when I frist start it up it is an incredible pleasure to drive, I can get rubber going into the first three gears, and its all good and stuff. However, after a few minutes, (I imagine when the car swithces from closed to open loop (or vice a versa, I'm not sure)), the car suddenly ceases to be powerful. It feels as thugh a cylinder has been chopped off. To prove this point, I did a clutch drop at 3 grand, and when the car is just turned on it, it makes an impressive smokeshow, however once the car is warmed up, a 3 grand clutch drop causes the engine to bog and feel like its knocking and bad. The only way to start from a stand still is to slip the clutch for several moments and move very slowly.

I figured it was an ignition problem, so I replaced all 8 spark plugs and wires, rotor, and cap. However the problem remains. I am very stumped with this one. I was debating/wondering if I could somehow force the car not to switch out of closed loop (or is it open loop?), and see if the car stays powerful the whole drive. However I 1) Have no idea how to fool it into staying into its first mode and 2) don't know if thats very good for it.

Any ideas or suggestions?

-- Henry

 

It could also be the fact that when the engine warms up, it transfers heat to the incoming air/fuel in the intake manifold very easily, which can result in less power.

 

I don't think this is the case b/c its a pretty sudden and VERY drastic change. The difference goes from a 3 grand clutch dump ripping tires up, to a 3 grand clutch drop causing the engine nto have enough power and bog completely, it feels as though the car is on 7 cylinders. If it was a heat transfer issue, the power drop could not be that noticeable, the car should at least start from a standstill at 3 grand.

 

Even if the SES lamp is not on, scan for error codes.