DaveT

Engine model would help with ideas. If it is an EA82 spfi, fuel starvation can cause power loss. It is also normal for the transmission to downshift when you floor it, there is a switch on the gas pedal that trips a valve to do this. Also 4000 rpm is not harmful to these engines, it is normal rpm at 65 mph for my 3 speed automatics.

#1 thing to help. Old starts. Don't rely on an old battery. 5 years is considered end of life for lead acid flooded cell bateries under ideal conditions. Ideal conditions are seldom seen in real life. Sometimes you can get away with using one longer, but it's capacity and capabilities are not what they were when new. It often does not take anywhere near that to start an engine, so everything seems fine. When it's cold it takes a lot more, and cold drastically reduces the capability in addition to the age effects and the higher demand of the cold engine.

Compare the friction of the old and new by installing.

Sounds like it. Sometimes that happens. I never had a reason to look at that particular wire / group. If it only connects to the diagnostic connector, it won't matter.

I never had any Turbos. I've run Amsoil 100% synthetic since the late 80s. And their ATF and gear lube. If it leaks, reseal it. Over 150K and or 10 years old, due anyway. Most noticeable thing is when they are cold, shifting is better - both the auto and standard shift. I run their bypass filters also.

That is not a freeze plug. It has a hex key recess in it. It is the access to the wrist pin on the cylinder adjacent. It opens to the crank case. The only freeze plugs are in the head, under the rocker covers.

FWD and 4WD hi would be for street use and speeds. Shift in and out on the fly. 4WD lo is a lot slower ground speed for a given engine rpm. Think of driving through woods, not on a trail. Up and down steep hills.

Yes, that makes sense. I was only thinking of FWD vs 4WD.

no clutch. Other detail - all 4 tires the same brand and wear. You can get away with slightly different - more so than with AWD, but may make switching in / out of 4WD less smooth.

Just be rolling, no heavy load one way or the other, not in a turn.

Must be something about where we vs mice are. Here they are a major threat to anything left outside. I've had them damage wires, lucky the car didn't catch fire. Build nests in the entire hvac system. They pull the fuzz from under the carpets and stuff it into the ducts, blower, anywhere. And bring in acorns,etc. Leave pee and poo everywhere. I'm in CT, so they definitely look for places to get out of the cold.

Kind of a side issue, but mice will infest it if they live in the area. Good idea about the fuel tank.

I made a wrench from a thick piece of aluminum and a couple of bolts. Square hole in the center for my torque wrench years ago. I use the fsm numbers. Once they are on, run it for 20 seconds or so. Re check the setting, as they often drift into place where they want to run, and the tension changes. Watch ebay for a used fsm.

I agree, the slightly high dose of HEET should not be the problem. No, you can't go by what newer cars do. They are way more complicated. Does sound like possible fuel starvation.

The neutral switch is only to prevent cranking if the car is in gear. Dead fuel pump, and or contaminated fuel is possibly why its running poorly. T a pressure gauge in the supply line at the TBI input port, then oyu know if the pressure is ok. 21PSI. Does not take much lower to start causing problems.

Since the engine is all aluminum, it pretty much is all the same temperature once it's been running for a while.

C&K switches makes some nice snap in rocker switches that are good and look nice. I think digital key and /or mouser sell them.

I think it was the xt model that had a button or 2 on the upper left bank of 6. Maybe the turbos had something there? Those are probably pretty hard to find. But if you did, they would probably be more of a pop into place kind of thing. I have thought about trying to convert the guts from the right side for use on the left, but never actually ran into the need to do it.

There are no guts behind them. Maybe take spares from other ones but lots of work moddling things. Assuming the upper left and right EA82 style buttons.

If it was only leaking, it only needed seals.

That is a pressure switch. I don't recall off the top.of.my head if it is a.low cutout or over pressure safety cutout. There are 2 variants of ac systems, need to know which it is, and what year. Is the engine an EA82? Is the compressor off by the battery, or right next to the power steering pump?

Freeze plugs by definition connect with the cooling system. On an EA82 they are under the rocker covers. I don't get as cold weather here in CT, but have noticed that synthetic oil helps with cold starts, as it does not get thick as fast. My Detroit Diesel-powered loader backhoe has a block heater and a battery warmer. Needs them, because the only thing that fires the fuel is the heat from compression. I run synthetic in that also, as cranking speed is what makes that heat.

14 v while running is normal, should be fine with charging. 10V at rest is low. There may be a partially failed diode in the alternator or other electric leak drawing the battery down. Sometimes batteries go bad early. Normal 5 years is max. I always put in the biggest one that will fit in the space available. But if it is cranking anywhere near normally, the battery is not why it won't fire.

if it is like the oil; light switch on my 76, it will light when you have near zero oil pressure.