speedysprocket

Well your grammar and spelling don't make you sound very smart.
I'll just try one of the other Ford forums. Maybe Mustang guys will be friendlier.

Aktech

If u don't know how to pull engine vac that's ok. I'll teach u how.

speedysprocket

I run vacuum gauges on my other two vehicles all the time. I know how to hook one up and read it. Previous owner put an after market cam in it but couldn't tell me exactly which one. Could something with too much lift be messing with the ECU too?

Aktech

I'm more than willing to help but we need to know a few things about the truck. Start with the basics and move on from there.

Aktech

I think it is the cam. These engines don't work well to other cams other then the stock ones. U can try playing with the timing.

speedysprocket

Play with the timing in what way? I have it set around 12-13 BTDC now. That is actually another question of mine. I remove the SPOUT plug, and my timing still shifts with changes in rpm. I thought it was suppose to stop all advance when that plug is removed.

Aktech

When u pull vac let us know if the needle is steady or a little jumpy. When was the last tune up and at least clean the cap and rotor. Souds like the plugs need to be cleaned also. We can test the map when we know what the vac is doing. No ur timing should not be jumping with the spout out. But it could be because of a vac leak or the map. Ecm is trying to fix it with more or less fuel.

speedysprocket

Will check vacuum this afternoon.
I bought the truck with the guy telling me the engine came out of a 91 Mustang. All they did was clean the outside, all new seals, new cam and they put the truck heads on it.
Spark plugs were new. Wires, cap, rotor, coil, PIP, TFI are all new. Does the TFI have its own default ignition curves built into it?

speedysprocket

So reading more and more and realizing this truck came from a Fox body Mustang guy, I'm realling thinking he put too aggresive of a cam in. I'll confirm the vacuum still, but to keep the stock EFI, is changing the cam my only option? Or is there a chip or ECU programming that can be done?
If I go to a carb, which I already have an intake and distributor for, what am I giving up over the stock EFI? Fuel mileage? Performance? I'd take carb reliabilty over this 80s EFI reliability any day...
In the end, I bought this truck because it was cheap and I needed something while I did body work on my other truck. Now I'm spending all this money on sensors and possibly a cam now. I will probably end up keeping the truck for a while, but just can't justify spending more and more on it. The good deal aspect of it is quickly vanishing...

speedysprocket

So looks like the cam is the issue. Vacuum at idle is about 10-11 in-Hg and 9-10 cruising. That would also explain the terrible gas mileage, around 8 mpg...
So what's my easiest option to fix this? What's the least expensive option to fix it? Should I just find a stock cam?
Forgot to mention is has shorty headers too, if that makes any difference.
Thanks for the help thus far!