1992 V6 cold start/cold air running issues

Hi guys -- new here.

Just picked up a '92 V6 that haaaaaaaates the cold. Living in CO, this is an issue.

It took about 20s of cranking this morning (air temp was mid 30s and humid) before it finally caught. Once running, it idled smooth, with the tach right at 750rpm when the engine is cold.

Driving out, it's slow, slow, SLOW. Like, I had an '81 Mercedes diesel before this, and it wasn't this slow.

After warming up, it improves a bit, but can still barely maintain 55-60mph on flat, and 45mph uphill. It stays smooth, it just feels like I'm letting off the gas -- like it's not getting enough fuel.

Notes: I've already changed the fuel filter to rule that out. The intake is not stock -- the PO installed one of those K&N intake things.

Important note: this behavior is only when the ambient temps are cold. When it's warmer, it's like a completely different engine. It is still slow starting, but only take about 5s of cranking vs so much cranking I weep for the starter and battery, and it can get to and maintain highway speeds without issue, though it's still slow because it's a stock 3.0 with an automatic and knobby 31s, but it can accelerate with other cars from a stop and get up hills without dying.

I did a search for these symptoms, and someone mentioned a temperature sensor. Is that an intake temperature sensor, which I assume would affect how the computer enriches the fuel, and thus kill power? Thanks for any help y'all can offer!

 

Did a little more research, and it looks like the coolant temperature sensor is what was meant. I didn't even think that could have been the issue because the engine temp sensor in the gauge cluster seems to work fine. Is it possible that the sensor works well enough for the gauge, but not well enough for the computer? No check engine light has popped up, and miraculously, I just passed emission yesterday (it was much warmer, so maybe I just got lucky).

A youtube video I watched said that the computer defaults to overrich running, which makes sense because that won't kill the engine like lean running can. Anyway, coolant temp sensors are cheap, so that's what I'm going to try next.

 

I just watched a video were a guy had a problem with that sensor because the housing it’s in was clogged and not circulating water.

Also you might check the battery/starter combo. Mine is from Colorado originally and I believe it has the cold weather package with a 1.5 KW starter and someone put the smaller battery in there before I got my hands on it. Although the battery tested ok on the machine it wouldn’t work. I put the bigger battery with more CCA and got it to start.

 

The TB on the 3VZE has a coolant line running through it that does two things. Coolant is circulated through the TB to warm it up and keep the throttle plate from icing up in freezing cold, wet weather. When your cruising with decent manifold vacuum and almost have the throttle plate slightly open the air speed creates a ton of wind chill which could ice up the TB. Without the coolant passing through it this could happen. The second thing is the TB has a wax actuated valve like a thermostat has but in this case the valve is open and this allows air to bypass the throttle plate when the engine is cold and idles above 1000 RPM to help the engine warm up faster. Then as the coolant warms up the TB casting this valve closes so that the air bleed screw is the only bypass and is what sets the idle speed when it is warmed up. There are several thermal switches on the small water manifold that is screwed to the intake manifold and this tends to get clogged up with rusty corrosion if a PO did not keep up with proper coolant replacement. That may be what is wrong with your coolant temperature switch. Also I have heard this wax actuated valve in the TB can fail and if it has in your case perhaps it is stuck closed making the easy start and fast warm up not happen. The other thing that can make a cold start hard is if the cold start fuel injector is not working. It is right above the two bolt flange were the EGR puts exhaust into the the plenum. All of these are worthy of a go through as most all these 2nd gens are north of 200K and in some cases 28 years of neglect or proud ownership has been played out and may be why it has been put up for sale!