Hard starting after long drives.

[arco777]

The X runs great otherwise, but after long highway drives (i.e. an hour or more) when I pull off the road, and after 10-20 mins try to start it, the engine just won't catch - it doesn't start until I crank it for about 20 seconds, then it will catch and sort of stumble along with lots of vibrations at about 300 RPM. If I give it throttle, it will have no effect or lower the RPM slightly for the first 15 seconds or so, after that I can rev the engine but it still idles just as bad and lacks power like it's missing. Once I put it in gear and pull out of the parking lot, the problem goes away. This is only after sitting for 10 minutes or more, and only just after a long highway drive... all other times it fires and goes instantly. The engine always runs cool so I don't believe it's a motor temp issue.

I searched the forums and didn't find a solid answer - there were allusions to it possibly being the fuel pump relay. Another possibility one person mentioned was the fuel pressure regulator - I haven't ever messed with those so I'll hold off for a minute unless anyone can add a point to that theory. Any ideas?

Another minor gripe, probably unrelated, is that sometimes (rarely) on said long drives, when I really get on it such as flooring it going uphill to pass, I'll hear a rattle from the engine. Is this pinging? I am using premium gas.

Thanks in advance!

 

[94Sport5Sp]

Hi:

I do not have any specific answers for you but it does sound like your x is running lean. The question is why? Some answers that come to my mind is "possible blockage at fuel filter", "loss of vacuum", "sticky MAF or TB", etc.

More information would be helpful. When the problem is present and you turn the key on do you hear the normal whine from the fuel pump? When the x is running rough is the CEL on? Have you tried pulling codes to see if any errors are set?

PaMnd

 

[arco777]

The system checks out clear, no codes stored and no CEL when it won't start. MAF was replaced with a new one recently and install of a cold air intake has had no effect on the issue. Throttle body has been cleaned and ported, problem existed before that. Fuel filter replaced recently. Vacuum's solid. The few times it has had the starting issue I don't recall if I heard the pump or not. Just replaced the fuel pump relay today.

I'd have more information but this has happened maybe 8 times or so - seems more common in this hotter climate (Arkansas), never had issues in Alaska.

 

[MrShorty]

Where it's intermittent, it will require some creativity, but the next thing I'd probably do would be to put a fuel pressure gauge on it the next time it acts up -- just to see if it really is a fuel delivery issue or not.