V12 engine problem

Insufficient fuel system pressure vs. a hot engine will allow the fuel in the lines to the fuel injectors to vaporize - vapor lock on a small scale. Should abate in cooler weather. The fuel system pressure can be checked by your car's shop.

Don't want to scare you, but get it to the shop immediately.

My car is an 84 with about 78k miles on it.

I was having the same problem intermittently for several months if I left the car sit a couple of days. Several stalls before it would chug and gradually after a minute or two it would run fine. Took it to the shop several times with that cold-start complaint and they couldn't find a problem, said it started fine for them.

I just returned from an extended trip, during which the car sat in my driveway. It wouldn't smooth out after starting, just kept chugging on a cylinder or two only as long as I'd pump the gas pedal. Had it towed to the local independent Jag repair shop, where it's been sitting a week.

The mechanic says, based on past experience, that he's certain it is plugged/trashed catalytic converters and that it needs new converters and repair of damage to the engine air injection plumbing caused by the heat of the backed-up exhaust. He thinks it is likely the result of a leak in an injector and ignition timing that's gone slightly off. He's telling me I'd be better off junking the car now to cut my losses, because even if he repairs it, reliability will likely go downhill rapidly from here due to age and mileage, and that the car, when running, may not be worth the cost of the repairs. I haven't fully accepted that diagnosis as yet, since I love the car and didn't have a lot of other drivability problems I would have expected with plugged cats (although I did notice light pinging under load)... but he knows more about 'em than I do.

Hope you get better news.

I would be really suspicious of that diagnosis.

First, check the ECU and make sure that it is functioning properly.

they can become really buggy and the problem can be heat related.

Broken soldering joints inside an electronic component can exhibit exactly the intermittant problems that you describe. Richard H. Kuschel "I canna change the law of physics."-----Scotty

Hello,

Low milage.

Not a big surprize, they probably left the car in a heated shop overnight and it started fine....

Sounds starved for fuel...

*Sounds*, *experience*? Sounds like time to run like hell from that guy. A vacuum guage can tell you, a pressure guage in the O2 port will prove it. Proof is in the methods employed, not some holy grail of guessing.

There is that *thinks* again. NASA *thought* it was ok that some foam smacked the wing....

Leak in the injector would cause some loping with the tell tale sign of black smoke or heavy fuel odor. Timing is important to check, especially since the distributor is known to have advance mechanism failures and water damage. A slight ping = timing issues.

He does have a point about the cost of the repairs, but it really sounds like he does not want to work on your car....junk it my way.

Yes like higher running temp, whistle or rushing air sound in the exhaust under full throttle, loss of power, glowing cats. Unbolt the darn things and look at the matrix inside of them. Besides, think about it, why would it start fine when it was warm? The cats are going to be just as plugged.

I would run like hell from him. No figures, no proof, all opinion.....Nasa is hiring.

Sorry for the thrashing, it was truly aimed at your mechanic.

Peace,

DieInterim