Hi ladies and gents
new proud owner of a 1990 f150 5.0 with a few issues, the guy i bought if from said he replaced the computer and a couple other things but was hard to get a straight answer out of him on any of it. 1st what should the timing be set at on a 5.0? (guy said he was setting it by ear, if thats the case he needs a hearing aid) and engine has a shake at idle but smooths out when i give it some gas. 2nd i have a exhaust pop/backfire only when the engine is warmed up. 3rd is i have a shake after it goes into 3rd gear and it dont seam to go into OD or maybe its skipping 3rd gear all together? it looks to have new plugs,cap,rotor,wires. i changed the VSS because it was shifting hard and that did take away some of the hard shift between the gears but still seams a little hard to me. both exhaust manifolds are cracked and i went to change them and the very first bolt broke off so that is going to wait till spring when i wont need the truck so much, i would just like to get it running better to make it threw the winter, i kinda knew what i was getting into only paying 1400 for the truck but the inside and outside are clean ... any help would be nice thanks

 

Pull all the plugs and do a compression check, the shudder and backfire makes me think you will find one hole has none or very low compression and if that is the case you will need to pull the motor.

 

thanks, i will check it this weekend ... i am going to put in a egr valve and a o2 sensor so i can do it then

 

Grab a tining light and warm the truck up. Then pull the spout connector and set timing at 10 to 12 degrees

 

Before or after top dead center?

 

Before. If he set timing by "ear" there is no way to tell where it actually is

 

well i finally had time to spend a day working on this truck, its funny how a engine runs great when ALL the spark plug wires are going to the right places ... the guy i brought if from changes all the sp wires cap and rotor, well he had the number 1 and 2 plug wires switched on the cap so both of them were firing but not when they were supposed to!!!! so i went from a 6 cylinder to a nice running 8 .... i will never NOT check someones work again just because they sound like they knew what they were talking about