All of the advices you have recieved are valid and based on others personal experiences.
The problem though is there is a hell of a lot of wires, connectors and relays IN ADDITION to the PCM (powertrain control module) involved.
The ways you need to approach this:
Quiz her, the shop guy under what exact condition there cranks - no spark - no fuel occurred.
This is a must-know. THEN you can set up to test and diagnosis only under these conditions.
Ambient cold to warm; to underhood hot, changes connector fits. Wound coils as in relays change much too. See?
Only happens after sitting ran and CLOSED HOOD hot soaked? Shhee. Have the hood open cooling just enough that it Never occurs in-shop. Twice this has kicked my ass. GM Cavalier. Toyota FourRunner. Both electronic ignition amplifier’s heat failures.
Both of these after sitting un-running for 20-45 minutes would restart and run fine too. Underhood cooled off just enough!!
EU mandated specs of this vehicle will vary from North America US/Canada/Mexico requirements.
Here after the early 1990’s manufactures were required to have positive fuel and spark shut off system in the event of a running vehicle rollover accident. They wanted electric fuel pumped gasoline NOT to be continued delivered to a wreck damaged hot engine area with electrical sparking capability. That is the system here I would focus on. Be different for a Ford, versus Chrysler, versus GM, etc.
The Chrysler types and imports doing the same I’d be swapping out the seldom used horn relay with the ASD (auto shut-down “SAFETY”) relay.
The PCM power relay if it had an intermittent should have set a code. Same for an intermittent ground on that circuit.
Sometimes (too damn often!) the problem is in the terminals inside a connector body, or worse the power relay center block.
Strong 12 vdc incandescent focused point light, and magnifying glass look over these disconnected in the could-be circuits. This will give you the satisfaction of doing something. And sometimes just the disconnection and re-connection will solve a become poor “fretting” connection problem. Why I had seem swapped out components, solve: then later “come-back” with re-occurrence. Three different new cooling fan relays once into the wife’s minivan until that harness relay plug end was poor 12v terminal connection overheat damaged enough to be readily visible.
Your problem is for sure happening on part of the vehicle NOT PCM monitored.
Do not be afraid to tap, wiggle, twist, jiggle components and wiring harness’s when this is happening. Needs two people. One person to continuously key try: the other to manipulate.
Ford sideways V-6’s due to failed hydro-elastic engine mounts are notorious for within harness breaking down the firewall to engine 64 to 128 wire harnesses. Then weird intermittent’s galore.
90’s Chrysler FWD sedans notorious for across the front chin-curbing and crossover harness damaging.
Dodge 4x4 pickup truck now know for droppped down the transmission harness rub damaing and intermittently to-ground pulling-low the PCM 5 volt circuit killing the spark too. In distibutoe HALL effect sensor is fed off of this circuit too. No Spark detected. PCM then shuts off the fuel injectors.
The Opel tech was saying well . . . . sometimes it is better to just be happy with the good six years and move on. Hey! She passed the kid-will-wreck-it learning curve! Good for you Dad.
You, me, another grumpy ol’ man stuck might 'cuss, swear, and refuse to give up on an intermittent.
But where a She-in-your-life’s safety is invoked better to buy out of problems and as much as can be afford into safety.
Why I took my wife’s 1999 minivan away at 8 years and drove it myself with accumulating systems failures out to 18 years. Did the same with her 2007 Hyundai after 7 years. Now 5 years into a few problems driving it out to my patience limit. Ha! Endless it seems low loss coolant leaks chasing me. If, when, it ever goes actual headgasket bad . . . . then bye-bye to the scrap yard.