98 jeep computer replacement does this need to be done by dealer

Nope not legally just rite the milage down in owners manual and keep recipient with it

The following are the general instructions on the start of diagnosing any electronically controlled engine or transmission problem.

The engine and the automatic transmission (transmission control is only for automatics, engine is still computer controlled no matter the transmission type) in this vehicle are computer controlled and in most cases when a fault occurs a fault code is stored in the memory of the computer control module. There are exception to this, such as the Mass Airflow Meter and fuel pressure problems. What must be done is to have all the basic testing done such as a scan of the system for fault codes as well as a check with a live data scanner tool for engine functions that are not within range of normal, a trained technician is required to know what is correct and what isn't, then based on careful diagnostics done from a factory repair manual the correct part is replaced or the wiring repaired or the computer replaced (known as the PCM or ECM,ECU), which is very rarely the problem. Other basic checks must be done as well such as mechanical problems with the engine as well as engine state of tune and mileage on the engine. The transmission can have mechanical issues as well such as no gear engagement at all or a failed pump or other pressure related problems. Also engine mechanical problems can and do cause many drive-ability related problem such as rough idle and other symptoms.

take it back to the dealer and have them check for correct installation of the recall
it is necessary to align the rear of a vehicle before the front is done or you will get "crabbing" which is what you describe
any work on the rear suspension will require that the rear be aligned first

All I can say is do some research online find a REPUTABLE shop and let them drive it until it dies. Three things are needed for an engine to run: spark, fuel, compression. I doubt it is a compression problem being that it is a new engine. Something is causing either spark or fuel to drop out, a good mechanic should be able to quickly identify what is missing from the equation. Find a shop with a lab scope that can test sensors that send signals to the engine computer. It could be as simple as a fuel pump getting hot and quitting. Good Luck!

The fault mentioned can be related to many issues but it will be good to have the vehicle checked for all the wrong codes, done the maintenance for the mileage clocked. Use good grade fuel, replace air filters, fuel filters, get the timing/ calibration done.

Some tips for getting more mileage.

http://www.fixya.com/cars/r6019480-tips_fuel_saving_hypermiling

Some vehicles have a sensor that turns this light on at a certain milage and it really means nothing, the dealer should be able to remove the light for a charge.Hope this helps and Thank You for asking.

I can give you some general advice, based on past experience, as I don't know what moter you have.
(6cyl 8cyl etc.) I would more often then not go with
the low milage used engine from a salvage yard.
As most of the 2nd engine swaps I have done have
been to replace rebuilt's from the chain store rebuilders, and some others.There some very good
rebuilders out there, but you have to do the homework. The best teacher is word of mouth,
especialy if it comes from a mechanical background.
If you decide to have it done tell your mechanic what
you wan't, a low to mid range milage engine(depending on cost diff.) installed. Then he will make
a couple of calls, get a price for the engine and give you a quote. I'll take a guess of about $1,200.00
-$1,500.00 Now you have to decide if the jeep is worth the money. Hope this helps. Good luck.

sounds like you have a coil or 2 arching out,they would have to watch misfire mointor on scan tool to see which cylinders are misfiring,also there is a tsb on that, requiring a reflash,but you said that was done,hopefully done right,dealer unable to find problem,what kind of tech is working on your jeep??? well good luck, hope this helps.

buy a couple bottles of gas line anti-freeze, add one to your gas tank. you should notice a difference almost immediately

it could be one of the many sensors the older the car the more possablty.