EFF26

Hey guys! 91 firebird 305 auto 700r4 TBI

Here is whats happening when you start the car it will idle up and down on its own and then just die. It will go from like idle up to about 1000-1200rpm then down and up and die. Then when your driving it sometimes when you slow down to a stop the car acts like it still wants to go when i am on the brakes. while driving the car runs fine unless you let off the gas then it just starts acting funny and wants to die. the ses light has not came on. could this be anything related to the torque converter. Reason I ask is sometimes when driving about 55-60 the car will vibrate and as soon as you touch the brake the vibration quits instantly. Thanks for any help

alexisgreene

About the vibration, check tie rods, bushings, ball joints, etc. Your idle problem, start with fuel pressure, compression, and a vacuum gauge. Check your idle air control as well. You high idle is most likely caused by a vacuum leak and your computer is trying to alter fuel and ignition to compensate for it and stabilize the idle causing your engine to act erratically. This will be less noticeable when you are on the gas because the throttle plate is open and your car will simply dump more gas to compensate for the leak.

james.gould150

i have a 91 z28...she starts and idels fine but after driving about 2-3 mins it stalls when in gear,i know i need to replace the speed sensor as my speedo doesnt work it wont stall in neutral or park,i know the iac,and map sensor and tps was replaced before i bought the car any i deas what this could be? it has a 305 tpi and auto setup all stock under the hood

alexisgreene

Check out your PCV and EGR to start with. Does it stall when you stop, when you try to accelerate from a stop, or while cruising?