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Frankie
07-20-2023, 10:21 AM
I've got a weird problem with my 99 Cobra that maybe someone here has some insight on.

It runs around 150 degrees when driving down the street at any speed over 60kph.
Even colder when the weather is really cold.

In town at slow speeds it will come up to 180, never overheats, fan comes on around 185-190.
Once fully warmed up, runs great.

At 150 degrees, it will hesitate as I roll into the throttle and feels down on power- probably as designed due to programming - it never gets out of the warm up section of the map.

I replaced the thermostat with a brand new OE Motorcraft one, exact same result.
Anyone ever seen this?
All i can find are posts about these cars overheating.

ZR
07-20-2023, 10:45 AM
That problem is bizarre, always the opposite.
Is it something that just started or always been a concern?
Always want them to run cool enough but that cold is not good for it.

Frankie
07-20-2023, 12:03 PM
Its been that way since before my ownership.

Frankie
07-20-2023, 12:32 PM
Both my factory gage and my Autometer gage show low so it cant be a gage problem.

Laffs
07-20-2023, 04:27 PM
Is that 150 on the coolant temp sensor from a scanner as well?

Is the car stock or modified/ tuned?

What are the fans doing are they cycling as they should or are they on earlier/all the time?

Frankie
07-21-2023, 10:22 AM
- I will hook up my scan tool and find out. Thanks for the suggestion.
I would say it will most likely read correctly because of the noticeable difference in how well it runs when hot.

- Car is running a canned 94 tune from my BDX tuner.

- Fans cycle as they should at what look like the right time.

Laffs
07-21-2023, 01:56 PM
Have you tried reflashing to stock and seeing if problem persists?

Frankie
05-24-2024, 10:27 AM
So nearly a year later and i finally have this problem solved.

I read an old Corral post about temp sensors being recalled in the late 90s.
Sure enough, the one in this car was reading low resulting in extra fueling and pulling timing.

To top it off, the Autometer temp gage reads about 15degrees low.
Now the car runs 175-195 all the time, power is back and no more hesitation.
Not bad for a $40 part.

RedSN
05-24-2024, 10:51 AM
Wow, two posts today solving long time plaguing issues, solved with simple part.
Glad you got it sorted out Frankie.