99 Explorer Hard Start and Rough Idle

[bigdawg703]

I have a 99 Explorer with the 4.0 OHV engine and it has 167,000 miles on it. It has a rough idle when sitting and if it has sit for a while and you try to start it it acts like it is not going to start then it kinda stutter starts. if it was just running and you start it back up it starts fine. I just did a tune up on it spark plugs and wires and its still doing it. Any ideas on how I can fix this?

Thanks

[shorod]

If your tune up did not include a new fuel filter, then you may want to change that out as well. Additionally, the tune up should also include at least checking the condition of the air filter.

If the fuel filter doesn't fix the idle concern and the air filter checks out okay, then check the fuel pressure. Your symptoms are somewhat similar to those of a weak fuel pump. You can also try turning the key to RUN, then off for about 5 seconds, back on, off for 5 seconds, then attempt to start it. If it reliably starts this way, then I'd certainly consider checking the fuel pressure. If it's low, replace the fuel pump. If cycling the key slowly before starting doesn't seem to help, then consider removing and cleaning the Idle Air Control (IAC) servo.

-Rod

[xFatcatx]

Heres a link with pics on exactly how to clean your IAC. Very simple job. This is for the 4.0 OHV, on the 4.0 SOHC the IAC is on top of the engine underneath the plastic intake cover and there is no black cap to remove. http://www.explorerforum.com/forums/...ad.php?t=84220

[bigdawg703]

Thanks for the help, I am going to try these things this weekend and hopefully one will be the problem.... hopefully not the fuel pump