Trouble starting car, hesitates during driving/accelerating

ALL_ROMEO

MEMBER
2000 MERCURY MYSTIQUE
4 CYL
2WD
AUTOMATIC
180,000 MILES

I recently purchased a 2000 mercury mystique.
First thing in the mornings or during the day, it hesitates to turn on. It also stalls while driving or accelerating.
I immediately replaced the fuel pump, fuel filter, battery, and spark plugs.
If it helps any, I notice the fan (radiator fan?) Comes on when first turned on even when the car is cool, and the fan pretty much stays on all the time car is on or driving.
I have even tried different fuel cleaners such as Seafoam to removes fuel additives, but to no avail.
Dont want to send you on a wild goose chase, but I know I need to replace the heater core and the a/c compressor clutch. Maybe this explains the fan being on all the time?
There is no check engine light on, so how can I check any sensors?
Thank you for your help.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

I don't think that is related so we need to stick with the hesitation. The fact that you suspected it was a fuel pressure issue is what we should stick with.

We need to check the fuel pressure while this is happening to find out what the pressure actually is.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Depending on what the pressure is we can determine the next steps, but I suspect this is going to be fuel related.

However, if it is not then here is a guide that will get us onto the next things that are going to cause hard starting and related issues:

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

I am thinking this is a regulator issue so let's start with this and go from there.

I am attaching the info on this below so let me know what you find. Thanks

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