I searched this forum and could not find anything in reference on how this 3.6 pentastar performs poorly in hot weather.

I have a 2019 Journey GT AWD with the 3.6. After owning this vehicle for the first few years, I finally got used to how this vehicle behaves thru out the year. During the hot summer months, this vehicle will run terrible. Feel like running a 4 cyl. Terrible acceleration and at times, there may seem to be a terrible lag time when you punch the gas to accelerate, it may take a few seconds before it responds. If it do respond, it has a very slow acceleration curve.

Now come fall/winter months, the vehicle behaves well. it responds when you need it. It accelerates as I expect a v6 would. Shifts with no issue. etc.

I am not sure if the computer/pcm is protecting the engine from overheating during the summer months so it just puts the vehicle into a somewhat halfass limp mode. You do not notice this issue at all during the cold months. It loves the cold...

I do notice however, the ambient outdoor temp sensor is like 10-15 degrees higher than actual temp. I heard the pcm monitors external temperature to optimize engine efficiency and wondering if this inacurrate high temps is messing up the computer and putting the engine in limp mode during the summer. I see temp readings on the display as high as 115-124 degrees when outside is actually 105--108 during the peak of hot summer in DFW.

 

Well your not to far off from what I was going to suggest, but you need a scanner to read actual intake temp, the ambient temp sensor is a separate standalone temp sensor, not the temp of the air going into the motor, however a sensor reading high could still potentially cause performance issues.

Cold air will always perform better than hot hair, because cold air is much more dense, you get a lot more air inside the certain dimension of air. 4 stroke motors don't usually suffer from this nearly as bad as two strokes, this is one reason you notice better fuel economy in the summer than the winter

How many miles on this unit? Has it had a tune up recently? Air filter? E85 or regular gas?

 

This vehicle only has 40k miles. Mostly hwy mileage vehicle is well maintained, etc.

Now I noticed this vehicle throttle lag occurs in winter. Just got back from shopping and when trying to get on hwy on acceleration ramp and merge with heavy traffic, there was almost a 3 to 5 second lag when I gave it full throttle. Scariest 5 sec pause ever. I am planning to get rid of this vehicle for something else that do not have this very bad throttle lag. I had it checked into. A few times. No errors or anything on diagnostics to show a problem I am glad to have kept my 2000 durango r/t. No fly by wire pedal crap. Instant response when I hit the pedal.

 

I don't know if this information is still needed.

This is what, I would do.

The ambient air temp sensor is used by the HVAC automatic temperature control system.

The sensors that concern this issue are:
ECT coolant temperature sensor.
IAT intake air temperature sensor.

First, display the engine coolant temperature, on the display screen in the gauge cluster.

What are the engine temps it runs at?

The radiator fan turns on at 220 degrees. Cools down to 214 degrees.

Is the coolant level correct?

The IAT sensor should be spray cleaned.

The throttle body (ETC) can be removed and thoroughly cleaned.

For the ETC there is a relearn function. That has to be done. Using a bi-directional scan tool.

Check the engine air filter that it is not clogged.

If you do still have the Journey. I can provide more help.

 

Thanks D16,

As I said earlier, all diagnostics checked out. All engine temp's are operating normally. Maintenance has been performed per schedule and some were performed much earlier.

Air filter check is clean.

It is just the nature of this Journey with the v6. The throttle response responds differently depending how much throttle you want. Under light to medium throttle, it responds as expected.

Under heavy throttle to full throttle, it reacts differently. It reacts poorly most times vs normal. Scary poorly when reaction time is critical. Such as accelerating into an onrap to merge with high speed traffic.

It feels the engine is just bogged down, transmission just won't shift to the right gear to let the v6 rev into its power band. I think more or less this 6 spd transmission is total crap. I do not feel much difference between 3rd gear and 4th gear.

Never a fan of these drive by wire stuff. Seems like cpu is super lazy when you need full throttle and it takes its time giving it to you.