just changed timing chain and tensinors after charging battery got cat system fault and open boot light

 

Ron, check your battery voltage. Any voltage below 12.50V is a problem.

Also, what model car do you have?

 

I have a 2001 s type 4.0 with 88,000
cam tensioner broke and replaced with new type tensioners guides and chain
engine runs fine no noise but have a rough idle

any suggestions so now I take it that the cat system has nothing to do with the engine

 

Its a suspension problem.

 

any suggestions on what to check next for the rough idle

 

No trouble codes? Definitely the battery as mentioned, but likely some sort of vacuum leak.

 

could I have a weak coil causing the rough idle and how can I check for a weak coil

 

with a COP (coil on plug) tester. Ford also has a coil "stress" tester, but you will find a COP tester will point out the coil(s) that are acting up.

About $80 - $100 on Amazon

 

After standing overnight and WITHOUT starting engine, what is battery voltage?