I drive my car about 3,000 miles each year, out here in Nevada. Most of its use is on the streets of Las Vegas, but each June I drive the 1000 miles round-trip to north Lake Tahoe. Last year the car started to buck and lose power about 6 hours into the trip, as we gained altitude. I had it looked at by a dealership in Carson City, after leaving it overnight in the lot. The mechanics could find no problem after road testing that morning. I left Carson City and drove the last 25 miles up to Incline Village where I had the local mechanic replace the air and gas filters. There were no more problems, even on the trip back south to Las Vegas.
This June, the car started to protest earlier in the trip up to Tahoe. At one point, the engine stopped completely. I managed to limp into Carson City where I stayed overnight. The next morning the car once more bucked and protested as I drove up to Incline Village. This time the local mechanic and I decided to replace the ignition coil and related parts. There was some wear of these parts so we thought the problem had been solved.
Yesterday, I drove north to Reno, which entails traveling up to about 8,000 feet in elevation, then down into the valley on the other side. Going to Reno posed no problem but returning, later in the day, brought on the old issues. The car bucked and the engine lost power. We managed to limp over the mountain and get back safely but now we are stumped as to what to do next. In all cases, the outside temperatures have been at least in the 90?s. I love this car and want to keep it as long as I am able to drive it.
Any suggestions???
You may have a failing fuel pump; renewing the fuel filter may have given it a few more miles. When a car loses power, it is usually not getting enough fuel, not getting enough air, or the iginition system is acting up.
I would have all these checked out by a competent mechanic before taking any more trips.
There is a test fitting on the rear injector rail where fuel pressure can be checked. This is a 4.5L V8, right?
I have an Allante with the same engine and similar issues. With my car, when hot #5 cylinder dies completely, producing a dead miss. The ignition checks out fine, and it runs fine cold and sometimes hot. But on hot days, after a 10 minute drive, #5 will drop out. I suspect a bad (heat sensitive) fuel injector but I’m still investigating before I tear into it…