On my 88 f150 300 m5od I've got an issue. The truck will buck at random times. Sometimes under load. Sometimes cruising. And when it bucks the tach and speedometer go all over the place. Could this be a possible vss? Ill be pulling codes when I get home

 

Not exactly what I wanted to find. Code 14 which is pip circuit failure. Distributor has been replaced which is why this is pissing me off. ****ty aftermarket parts these days

 

At least you know what the problem is now.

 

My truck has the same problem, the only difference is at times the speedo will just drop to 0 for like 5 min, 93 351 e4od though, and I thought it was VSS too

 

Which distributor do I have? Duraspark II or tfi IV?