Trouble starting

The last person who had this problem also figured out it only occurred in his sloped driveway when the level in the tank fell below a certain point. Coast it out to the flat road in front of his house, then it would start normally. The cause was related to the fuel pump assembly, and as I recall, his truck had just one gas tank. The problem was not the pump itself. It had to do with the bowl the fuel pickup tube sits in.

For anything related to vacuum hoses, there will always be a dozen or more vacuum hose routing diagrams in the service manual to cover all the variables of engine size and optional equipment. The way to insure you are looking at the right diagram for your truck is there is one on the emissions sticker under the hood. If the part you are looking at is not labelled, the people at the dealer's parts department will be able to figure out what it is and what relation it has to engine performance or emissions.

The next step is to connect a scanner to view live data when the problem occurs. In particular, I would be interested in seeing the intake air temperature sensor reading and the coolant temperature sensor reading. Both of those sensors have an extremely low failure rate because there's just one component inside them, but that did not stop Ford from having a huge problem with their coolant temperature sensors in the early 1990's. Those caused erratic temperature readings accompanied by erratic idle speed, but if the readings were bad enough, hard starting resulted.

Look at the reading from the intake air temperature sensor too. That one has a big effect on how much fuel is squirted in for the priming pulse to start the engine. If the reading is considerably higher than the actual air temperature, not enough fuel will be sprayed in. That is where starting fluid can get it started.

The scanner will also show the number of milliseconds the injectors are being commanded to open. If those are lower than normal, looking at the sensor readings will provide the clues as to where to look.

Every manufacturer other than Chrysler relies on a mass air flow sensor to calculate how much fuel is needed to go with the air entering the engine. Be sure there is no loose hose clamps or other leaks in the fresh air tube between the mass air flow sensor and the throttle body. If any air sneaks in that does not go through that sensor, no fuel will be included in the calculations to go with it.

Fuel pressure must be measured with a gauge. Too many people get fooled by just pressing the valve on the fuel rail. They see a squirt and assume that means pressure is okay. In fact, with fifty pounds being normal, many Chrysler engines will run down to less than twenty pounds, but they may not start at that low pressure. A lot of GM vehicles will not start or stay running if fuel pressure drops just five pounds from normal.

I am thinking like Cardiodoc. What does the fuel gauge say? There may be water or junk clogging up the fuel screen on the fuel pump. Ehtenal does clog it up at times. If the vehicle has sat for a while I would drain the fuel tank then before refilling it with good gas put a can of what they call Seafoam, it helps get rid of the water if and by and helps clean the screen that is on the end of the fuel pump. If a vehicle sits for any good length of time the fuel an and sometimes goes bad. I guess the sure way to see is take off the gas cap and smell the fuel. If it smells rotten then cleaning the system would be a good idea. With the vehicle at an angle it may be picking up if there is any water in the tank.