I’m trying to figure out a cold start gremlin on my 1998. On cold mornings the truck is difficult to start, the colder the weather the tougher it is. When it is above 50 or so it has no mentionable issues, but the farther below that it goes the more it doesn’t-want to start. At 35 it starts, but only after about 10 seconds of cranking, I have not tried colder temperatures yet. After starting, if I turn off the ignition and then restart it it starts up fine.

I have already replaced the plugs and wires, the air filter, the PCV Valve, and rotor, the distributor cap and rotor, the fuel filter, and both the intake manifold gaskets. The catalytic convertor is questionable.

Since replacing the intake manifold gaskets it seems to run much better and has noticeably more power, but I am still having the cold start issue. Any ideas?

My working theory is that it is fuel pressure, that either the pump is going bad, there is a leak somewhere in the system, or the injectors are clogged and that the reason it takes so much to get started but restarts fine is because fuel pressure needs to build, or blast gunk out of the fuel injectors. But why would that be sensitive to temperature? Am I on the right track?

I’m thinking about possibly switching to premium gas and adding a bottle of injector cleaner every time I refuel, could that help? Could it harm anything?

 

Does a code reader give any codes?

I saw a car repair video that diagnosed a similar issue. After checking that the engine was not getting flooded, he figured out it was an air temperature sensor. When colder, the engine needs more fuel I think is what he said but if it doesn't know its cold out, it won't start easily or run smoothly until it warms up.

 

No codes that I’m seeing, I haven’t plugged it in to a scanner lately, but the last time I did the only codes I saw were for a random cylinder misfire (being caused by the leaking intake manifold gaskets I was told, but may have just not cleared from the bad spark plug wires, and a catalytic converter error which was being caused by the misfire. Both codes were cleared and the light has not come back on.

 

My 96 Jimmy is doing the same thing lately. Most of the time if I cycle the key 3-4 times to let the fuel pump prime it starts. I just picked up a fuel pressure tester so I'm going to diagnose the fuel system this week. I did replace the fuel pump this spring but I went with a cheap one off of Amazon.