Car stalls when driving.replaced fuel pump worked fine for 3 weeks now does it again.previous mechanic left air in take throttle body cleaner so I'm guessing he used that to clean those parts? New mechanic is stumped says he doesn't know but tested fuel pressure throttle body and fuel injectors, the ignition system and says all good. Says somehow car loses fuel pressure but doesnt know how or where. I checked the main relay for clicking. Are there supposed to be 3 clicks coming from the main relay when turning the key in ignition? I'm only hearing one when the car starts running so the position 3.When the car stalls out of the blue it is usually at stop lights or changing gears from 1 to 2.i have noticed that it takes the car more time to warm up in the morning..When you start the car and you are in park you can hear the engine but the sound is of uneven intensity.its not sputtering just uneven. The new mechanic said 2 out of 3 times it stalled again at stop lights. Charged me a bunch for diagnostic that produced no diagnosis. Car is manual after aftermarket changes by previous owner. Should I just give up o this car? Has more than 1300000 miles on it has spark plugs replaced recently. Help and thanks

 

Any check engine lights?

Try another used or working Main relay and see if it stalls. Also try cleaning the IACV it might be dirty and staying closed when you come to a stop causing the engine to stall.

 

Thank you for answering.yes, check engine light comes on
For any of these is disconnecting the battery necessary? For the main relay? And is coolant gonna leak when removing IACV or can I clean it in place.
Obviously, you can tell how unknowledgable I am, but the engine runs real well even with the intensity fluctuations when in park but I'm trying to solve this myself. These big shops are interested in replacing things but never take care of the smaller details.

 

Start with retrieving the ECU code because that's going to point to the main issue.

When you disconnect the battery it will erase any codes so don't do it until you retrieve the OBD code then after you know what to fix you can clear the code. A scan tool will work the same erasing the code I recommend buying one from Harbor Freight they are like $25.

Coolant will leak if you disconnect the 2 coolant hoses on the IACV on B series engines you can remove the IACV and clean it with out having to disconnect the coolant hoses but don't do any of this until you get the ECU code and go from there. If you do need to clean the IACV just drain the radiator and remove the IACV and use brake parts cleaner and spray it inside and clean out the gunk and install after a few mins when its dried out.