This problem may require the services of an expert. Erratic brakes and a stumbling engine are ingredients that can lead to an accident. I'm no expert in this arena, but here are my thoughts. On startup, you are missing the vacuum boost to the brake system, and somehow, later on, some or all of the boost is regained. The engine stunbles consistent with a vaccum leak. You've checked for vacuum leaks, but may have missed the "big" one, the vacuum boost unit itself, or the vacuum accumulator and associated vacuum lines. At this juncture, I suspect that the vacuum boost unit of the power brake assembly has failed, and admits an overload of air to the intake manifold (when the brake pedal is depressed) causing the fuel mixture to lean out. Often associated with the vacuum booster is a small vacuum tank called the 'accumulator'. It will be attached to the vaccum lines that supply the vacuum booster. It's purpose is to have at ready a goodly supply of vacuum volume to handle a suddent demand, and to keep the heater controls happy during this step demand. This tank is very important if the the vacuum fitting on the manifold is 'ported', that is, has a orifice within it to restrict the amount of air flow in case of total vacuum system failure. This tank may have a one way valve. This is the vaccum source that aids one more application of the brake after the engine dies. This tank may be made of two plastic halves and ultrasonically welded together. A leak along this seam is possible. Do you have a hand pumped vacuum tester with vacuum gauge? If you do, remove the vacuum line that feeds the vacuum booster and apply vacuum directly to the booster. Pump down to a vacuum level, say, 10 psi, and hold. Can the booster hold vacuum or does it leak down fast. If it can not hold vacuum, it is leaking. You may have to block the brake pedal down past the valving point for this test. There is a valve in the booster unit that applies vacuum when the brake pedal is depressed, and it relieves vacuum when the brake pedal is let up. This valve can be a problem source.

Lots of ideas about what is wrong, but the answer lies in testing the system correctly. Behind the LF strut there is a gray connector with a red wire that does not appear to connect to anything. Take a test light and connect it to the battery positive terminal, and to that connector. The relay when turned off actually closes that connection and that feeds the fuel pump and is called a fuel pump priming connector. If the test light does not turn on the circuit is open or has excessive resistance. When you turn the key on without cranking the engine the relay will be turned on for about two seconds and then turn back off. The testlight should turn off, for that two seconds and then turn back on. Tell us what happened with this test, and then I'll tell you what to do next.

The idle speed is controlled by the computer with the idle speed control motor (ISC). Its unlikely the ISC got damaged with the cylinder head being taken off and put back on. There are two likely causes for such a high idle speed, one would be a large vacuum leak, something like the power brake booster hose not being reconnected yet. The other likely cause is either the computer is commanding the high idle speed, or else the computer cannot control the ISC. Inputs like power steering pressure, AC clutch command, and the transmission shift position cause the engine to need to idle faster to prevent stalling. A false input from one of these causes an excessive fast idle problem. The computer looks at inputs such as engine coolant temperature to control fuel delivery and to produce the cold engine idle speed which would be about 3000rpm right when the car is first started, and then it should drop quickly. A break in the wiring between the computer and ISC could be the cause for this problem. The ISC allows air to flow around the throttle plate to control the idle speed. This passage is right at the top of the throttle body, and it should be easy to confirm if the air entering the engine is in fact flowing through the ISC passage. (Loud sucking sound, and idle speed can be affected by restricting the ISC intake port with a finger. Its always possible the ISC has simply failed in the stuck open position, but its not anyone's fault. Cars break whenever they want to.

Following the uphill with engine running ... and downhill with it not ... made it home without further incident. I'd had further trouble, in that the warning lights on the dash that turn on when one turns the key on but go off when the car starts ... had been staying one. And the engine was running much too fast when it was sitting, idling. On Monday morning, checked oil - O.K., down a little, added some. Checked coolant, down a little, added some. Had moved car from garage to by the house ... then it didn't want to start ... after sitting for about an hour, it did. Stopped at the end of the lane to get the mail, turned engine off - wouldn't start. Pushed it back up a slight rise in the lane, pushed it down to get started, but not enough speed to start. Let it sit for a half hour - wouldn't start. Called CAA ... they said it's be about 45 min, later auto meesage said about an hour, but the tow truck arrived in about 45 min., asked what was wrong, I said starter wouldn't turn engine over. He asked about tapping the starter with a hammer ... but couldn't find it, told me to try to start, I said he should, that I'd tried ... ... so he did ... and it started! After some colourful language on my part, I told him that I'd be O.K ... and took off immediately, before the engine heated. I thought after I was on the road that I should have asked him whether he'd come from the city, in which case he could follow me down the road that I was going on for about 6 mi., till I turned away from the city, about a half mile from the garage. More of the operating uphill, not downhill for about 5 miles, till engine began missing some as I was climbing an overpass over a freeway. So, over the top, I stopped at the side of the road for some recuperative/cooling time - though I hadn't seen the heat gauge rise high, but it rises slowly and I'd been running the engine in short bursts. Too impatient, I guess (not wanting to sit, doing nothing? maybe should have brought a book?) ... ... after 10 - 15 min., pushed it a bit, it started rolling down the hill, the engine started ... ... but it was still missing ... and after a few hundred feet of travel .. stopped, so I coasted to the side of the road. Within a mile of the garage, I walked there, they pushed the car in. It seems that the belt driving the alternator had broken, that produces electricity to replenish the battery's charge. Though it seems that the belts running the water pump, power steering pump, etc. were intact, for some reason the water pump wasn't working ... so, with very little water circulating through the radiator to cool it, the water in the motor heated rapidly. Power brakes and power steering were operating O.K. Fortunately, they'd replaced my battery last month, so I'd been running on that one battery charge for all of that time. If I'd known of the need, I could have recharged the battery Sat. overnight, at home. This library closes at 4, so no dice here on Monday, after the garage... and only the downtown London library opens on Monday ... but parking meters near it are rather expensive ... so sometimes I park half a mile away, then walk ... but didn't, yesterday. However ... I'd made a special call to son on Sat. night, saying that I had pizza ... and would bring it on Sunday ... ... but had forgotten, and had supper with son on Sunday. So I took the pizza in on Monday and we had pizza for supper; forgetful Dads can be something of a pain. I'd thought to go to the city library after, but went home instead. So - it looks as though things are back to normal. I'm thankful that, most of the time, when I'm in the car ... it's as full of hot air as necessary ... again! ole joyful