we own a 95 ford f150 with a 4.9l engine. I am having trouble with the timing of the truck. I disconnect the spout connector and set the timing to 10 degrees btc with no problem. With the connector disabled the engine will hold that timing perfectly but after turning off the engine re-connecting the spout connector the engine timing bounces up and down anywhere from 10 btc to 22 btc. any idea what the issue could be? we have replaced the distributor four times with a brand new cordone distributor and still the same results.

 

My guess is you have an issue with the PCM. It send a signal to the distributor to adjust the timing based on other motor data (signals) of fuel consumption, motor RPM's and air fuel information. I would pay an independent shop (electrical) to put it on a computer and read the PCM data that is stored. Should be about $65 to $100. A guy on this forum does that testing. RnlComp.