lemccullough
Newbie
Hello, I am a newbie and this is my first post/question. I have a 89' chevy truck 350 tbi completly stock, engine replaced 150-200k ago. started having issue with the vehicle bogging down during take off and then clearing once i got up to 20-30 mph, tried spraying carb cleaner ect but nothing helped. After a couple of weeks it started out with the bogg down and stayed that way no matter what, its been about 3 months now. I have read hundreds of posts and have learned a lot from you guys but nothing that addresses this issue in particular. I have new plugs, wires, sensors, fuel pump, filter, rebuilt tbi and regulator, distributer, coil, knock sensor and timing chain, cam looked good. I have set the timing to 0 and cleared ecu by disconnecting battery, then reconnecting ecu wire bypass and then restarting only to watch my timing advance 12 to 14 degrees slowly drop back to 0 within about a minute, I have tried this with knock sensor disconnected as well, no difference. i am told a scanner for this year vehicle probably wont tell me much. The dealerships wont touch it because its to old and I beginning to feel I know as much as the basic mechanic. I cant hear any unusual noises. I did a fuel pressure test it seemed fine ( 12lbs) I have done a compression leakdown test a regular compression test and all that seems fine, changed out the ecu as well. when i first start it and before the timing drops back to 0 the engine runs real smooth and then once back to 0 you can hear a little pinging noise. If anyone can help me I would greatly appreciate the help
