Car engine stalled every 50 Km

Maintenance/Repairs
1

Hi Everybody,

I have a 2 years old car designed based on Peugeot 405 and the car has gone 35000 km so far. Last week I was on the road for about 2500 km. The first 300 km the car was fine, the AC was on as well. It was 45 degree celcius outside. Then suddenly I felt the engine lost its power and the car’s speed reduced and the electricity of car went of. I restarted the car and it was okay immediately and I went for 10 more kilometers and it stalled again. I restarted this time after 10 minutes and It brought me to a big city (80 km) without stalling but again in the traffic of that city it started losing electricity every now and then. I showed the car to a mechanics and he changed the double relay on my car. He also checked my battery and It was 100% fine. Then I continued my trip for more than 1000 km without any problem (I went to the mountains part of country which was 20 degrees cooler in the afternoon). Uphill and downhill was okay and no problem. In the way back home, again in the hot summer, the car started stalling every 40 to 50 kilometers and after getting cool it was working again.
Another mechanics checked my car and he said I have to replace the fuel pump which I did.
However, this makes me feel worry when overtaking with the car. Still when I turn the AC on the car loses a bit of it’s power somehow that in the first gear I feel it is going to stall again if I do not press the gas pedal enough. what is wrong with the car in your opinion? MAP sensor? ECU? Electricity cables? Coils? Spark plugs? what else?

I have done the following before the trip: the spark plugs gap changed to 0.75 from 0.9 since it was mentioned in the manual of the engine. During the installation of sparks one of them felt into the ground but it looked like fine. Besides, the mechanics cleaned the stopper of the engine before the trip and reset the ECU afterwards. I was using a GPS also during the journey connected to the car.

Thanks in advance everybody.

2

Did your cars overheat at anytime?

3

Yes, the temperature was after stalling higher than normal. The double relay was also hot after stalling. What do you think?

4

Some cars will either shut down or go into limp mode if the engine overheats to prevent further damage. But I would think your car should be able to handle 45 degrees Celsius but maybe not.
By the way, when the car is cold, did you check your coolant level.
Is the car under warranty? If so, have them check it.

5

If it ever stalls then won’t restart (but still cranks ok), check to see if the problem is spark or fuel. Probably the easier way to do this is to spray some starter spray into the air intake. If it starts and runs briefly, then stalls, it’s not spark, there’s a problem with the fuel system.

Suggest to also do the basic battery/alternator diy’er test. Before first start of the day the battery should measure about 12.6 volts. Immediately after starting the engine, 13.5-15.5 volts.

6

One of spark plugs (NGK) was cracked. Stopper also replaced today.