99 Chevy Malibu twin cam 2.4 engine. Loss power while in cruise control, misfiring, check engine light flashing

seldom plugs and coil
more often bad injectors , low fuel pressure or vacuum leaks

check and test battery and alternatot --if good inspect cables and connections when battery fails or alternator doesnt charge the car will shut down no power to electronics

the reason for the misfire and loss of cruise control is because the electrical system has an intermittent power failure . It will be difficult to diagnose in a shop because of the condition that is causing it . Some items are , dangling items on ignition key, loose /dirty battery connections, loose dirty earth connections, alternator drive belt condition /tension , loose fuses, loose ECM wiring fittings , faulty immobiliser, dirt at the cam/crank position sensor. Take it to an accredited shop that can get computer access to the CPU /ECM program and on their laptop they may be able to pinpoint if there is a problem showing

two things missing. Spark plugs itself, and o2 sensor.not mention

who they ? they did not tell you why ? could be spark plug wires, do a tune up, include new air & fuel filters, spark plugs, etc., you need # 1 spark plug to fire in order to start engine. winter time brings out all the problems, get a repair manual from a parts store, it will help you like, like having your own mechanic, just do it !

check to make sure catylitic convertor is not plugged. if it is ok, then put a code scanner on to read codes, may have a bad 02 sensor. if you dont have a scanner, most auto parts places will scan vehicles for free.

P1665 Evap vent solenoid control circuit

I would've started with the coil packs, modules, boots and plugs myself. They give many problems on the quad 4s?.

bring the piston no 1 on the top position check the cam shaft si moving freelyon the outer side of the shaft there are 2 gear with 14mm bolts and 1 extra whole, put a long bolt in the empty space and try to turnthe engine the bolt will go further in the space than the timming is set put the chain on that should do

The most common problem for a misfire and a flashing check engine light is the ignition coi on plug.
Each spark plug has its own coil pack. With a coil pack failing it will also cause a airflow code as the car will start to run rich. With the vehicle misfiring it can also inhibit the Cruise control but it will not necessarily bring on a gearbox fault. The most common cause of the gearbox fault light coming on as you describe is usually a weak battery.
I would replace the coil pack and have the battery tested.
Thanks and good luck
JPTCAT