My 99 Durango sometimes runs real sluggish and it would be hard to get it up to 70mph but the rest of the time there are no problems and the suv shifts normally and HAS GREAT POWER It has a 5.9 engine in it. I'm thinking it's the fuel filter being clogged or dirty. Tell me what you think

It will cost more that the SUV is worth.

Sounds like your AIS (Automatic Idle Speed) motor is working sluggishly or intermittent.
Try cleaning the throttle body and/or replacing the AIS motor.
I used to see that a lot working at the dealership

Couldn't happen just from replacing timing cover. Now if you replace timing belt/chain then yes it would be sluggish or not run at all. Sound more like you have issue with cold start valve.
Also, the accumulator is a likely place to begin, particularly because you say that it's only the first start that has hard cranking. A properly-functioning accumulator keeps the fuel system pressurized enough to open the injectors without a lot of cranking. If pressure bleeds off due to a poor accumulator, the fuel pumps have to run a while in order to re-pressurize the system, hence, long cranking times. The quick test is to cycle the ignition key 3-4 times before you attempt to start the cold motor so that the pump runs each of those times and is allowed to build up some fuel pressure before the engine is started. If that test helps, you've identified a fuel pressure problem, almost certainly the accumulator.

Check your fuses and relays might have blown when jumping the other vehicl

sounds like you have moisture in the gas tank. there's plenty on the market that will take moisture out of gas tanks. Home Depot, Menards, etc.

Kdog

PO741=tcccs solinoid.I had to replace one in my old ladys car.it used to shudder real bad also when the converter would lock up and throw the PO741 code..not real hard to replace and only about $40.00 for the solinoid from the dealer.

Best thing to do is go to an Auto Zone and have them scan your truck for any DTC codes. Auto Zone scan free of charge, there is just to many things that can cause the engine issues your running through such as detonation during acceleration due to timing issues to lack of fuel pressure. Good luck and keep me posted, be glad to help you get your truck running 100%

Take to Auto Zone and have the computer control module checked. Normally Auto Zone performs this service free. Or you could remove the computer modle and take it and have it checked.

Google for a refurbished PCM "Brain" and call the guys from the Florida company -- my 99 Durango had similar problem and I replaced the PCM < $300.00 and no problems since.

one of the universal joints on the driveshaft is bad