
Ask A Question - Help - Register - Login

1998 Ford Expedition 5.4 engine pulse, drive,net idle

Sent to Car Experts September 25, 2005 6:46 a.m.

1998 Ford Expidition; the motor, it pulses up and down. The motor is a 5.4ltrit has 98,000 mil. 97 octane in the tank, fluid levels are good. maybe a vacum leak?

Customer (name blocked for privacy)

Status: Closed Value: $100

Answer
September 25, 2005 7:48 a.m. (1 hour and 2 minutes later)

ACCEPTED

Although a vacuum leak will effect the idle, it normally doesn't get erratic like that but it just causes the idle to be higher due to the extra unmetered air be introduced. By all means check for the vacuum leak anyway but I suspect your issue is with the IAC (idle air control). Make sure no one has messed with the base idle setting. That will cause it to hunt also. I suspect you will end up changing the IAC. Here's what it looks like.

Images available only to Customers.

__________________
If I was helpful, please click the ACCEPT
button.

1 Other Expert Agrees with this!

Hammer Time -- L1 Master Technician -- 98% Positive Feedback on 2710 Car Accepts
ASE Mastertech with Adv level Engine performance cert.

Think you can answer this question?
Login or Become an Expert

Related Answers:

	DISCLAIMER: You acknowledge that any information you may obtain from individuals you contact through use of the Just Answer service comes from those individuals, not from Just Answer!, and that Just Answer is not in any way responsible for any of the information these third parties may supply. The site and services are provided "as is" with no warranty and no representations are made regarding the qualification of an Expert. Responses and comments on Just Answer! are for general information and are not intended to substitute for informed professional advice (such as medical, legal, investment or accounting) and do not establish a professional-client relationship. Just Answer! is not intended or designed to address EMERGENCY QUESTIONS which should be directed immediately by telephone or in-person to qualified professionals. Please carefully read the Terms of Service.

Just Answer! > Car Repair > For Questions