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Problems going uphill, sputtering & stalling, slipping?

30 year old Maserati Quattroporte III, well maintaned by PO as far as I know. 4.9l V8, Weber carbs, Chrysler Torqueflite 727A transmission.

The car keeps losing power (especially uphill) and goes slower and slower until I have to pull over to the side of the road, and either (at first) wait for a few minutes, then continue on (the car works ok initially, then displays the same symptoms) or (later) the engine dies. I let it rest for a minute, restart the engine, and continue on (again working fine to start with, then dying again after anywhere from a few hundred meters to a few kilometers). The trip I made on Friday went fine, even driving up the steep undersea tunnels (7% grade). Not so today for the way back. In fact I was concerned we might end up stranded in the tunnel!

I also noticed that it seemed to get worse and worse, even up gentle rolling hills, and that when I was closer to home (and had called a tow truck) I was unable to keep the engine running at all. Every time I’d start it would come to life instantly, then run unevenly, sputter and die.

I had assumed that my transmission was falling apart and it was just dying a little at a time. However, the fluid is clear red, there was no brown/black or any smell of burning, and the level on the dipstick is perfect. I never felt any slipping or surging before today, and now it’s in all 3 gears.

On a trip this afternoon/evening, the same lack of power happened in all gears. I had assumed it was the tranny just giving up the ghost (which it may still be, for all I know) since it felt a little bit like it was surging/slipping, but when stopping the car, then starting from a standstill, it worked fine for a while before getting all weird.

Luckily for me a friend was on his way the same direction an hour or two behind us, and gave me a hand. He thinks that what I was experiencing sounds a lot more like a problem with the fuel delivery system, specifically a leak/air coming into the fuel system and starving the engine of fuel. He says that’s probably why it sputters and dies, esp. up hills. The tow truck driver said that if the tranny was shot or even just slipping, it would slip all the time, and even from a standing start, not just after driving for a bit. At this point I’m pretty unsure what the problem is, or if there might be two unrelated problems (fuel delivery problems + transmission problems).

So while I look around and see if I can find someone qualified to have a look at the car asap, would anyone like to play armchair mechanic and suggest what might be the matter? Are there any diagnostic tests I can perform to rule out specific problems and help narrow things down?

Funny enough, I noticed this morning when I started it (front of car pointing up on an incline where it was parked) that it ran rough, sputtered and died several times. Usually I can start her up and let her idle until water and oil temps are 50C or higher before driving, and the engine runs smoothly all the while. Not so today.

Hope someone can offer some friendly mechanical advice. I like working on cars, but still have a lot to learn…



The tow truck driver at least is right, if the transmission fluid is full and you are not adding fluid, it should either slip all of the time or not at all. A transmission often does begin to slip in one gear or another first, and often until that particular gear is unusable.
As far as the loss of power goes, that could very well be something like the fuel pump or a carburetor, and it might feel as if the transmission is slipping during power loss. I would guess that you need to start with fuel delivery at the carburetors and backtrack to the fuel pump. One thing to look for is an overly rich fuel mixture, which would produce black smoke from the tailpipe(s) and fouled (black, powdery) spark plugs. A simple (but expert) adjustment might solve the problem.
Hope that helps.

This re-reply might repeat itself. I think my last answer got lost.
It occurs to me that the mixture might be too lean, not too rich. This would accomodate your complaint that the problem is intermittent. Weather could be factor, as well as too little oxygen (as in a tunnel). Again, see if you can find anyone to adjust the mixture. Otherwise, you need to rebuild the carbs.

Thanks for the advice kizwiki.

The carbs were professionally rebuilt by the PO (I have the receipts and pictures documenting it) as well as tuned. There is a lot of soot in the exhaust, I don’t know if that’s normal or not as this is the first car of this type I’ve owned.

The weather was very wet and cold, which would affect the mixture, definitely.

I’ll do a backtrack from the carbs, filters and back to the fuel pumps and see what I can find out.