My girlfriend and I picked up a 1999 Ford E150 cargo van with 242k on the clock yesterday. We bought it from a friend who got it in exchange for doing work on a guys snowmobile so we don't know the history of this van but it looks like the previous owner maintained it well.

Anyways, at idle it runs a bit rough, the vibration is more than what it should be. However, when accelerating the shaking at engine gets considerably worse especially when in third gear. If I take my foot off the gas it will go away but give it just a bit of gas it feels like the motor mounts will break right off! I tried shifting to 1-2-D and same thing happens as if I left it in D.

Today I took a look at the engine quickly and spark plug wires looks like its been replaced and are still good, checked two spark plugs and they looked good but I plan on replacing all six tomorrow anyways so decided not to check all of them. However I didn't take a look at the vacuum line so I don't know what shape its in or if its leaking. Thermostat probably needs to be replaced because the engine runs a little cold and coolant is very low.

I plan on changing the oil, filters, thermostat, spark plug in the van tomorrow and I'd like a suggestion of what else to replace or look at to diagnose this problem? Any tips would be great!

 

I forgot to add: there are no CEL lights on although the ABS is on but it's unrelated..

I'll also check the spark plug wires o make sure they're in the right order, I found that they're laid out like this:

firewall
engine
3 6
2 5
1 4
front

firewall
coil
3 4
2 6
1 5
front
Firing order; 1-4-2-5-3-6

Is this right?

 

i do not know if this will help you out but ......i have an f150 and it would shake like i was driving over rumble strips the wipers would shake off the window...mine did it at about 60KM and was good before that speed and after that speed ...the fix for that was reprogrammed the PCM/TCM in the tranny they also lubed the splines of drive shaft slip yoke now all is well and good this was done at the dealer hope it helps

 

My 98 F150 4.2 2wd also has a very bad shake. Almost like a misfire. But no CEL. Down on power too.