94 F250 w/351 startup and idle issues, MAPS? - Off-Road Forums & Discussion Groups
Ford 67-96 F-Series, 78-96 Bronco All discussions of 67-96 F-Series Trucks and 78-96 Broncos

LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 11-26-2004, 07:34 PM Thread Starter
Join Date: Sep 2003
Posts: 14
Thanks: 0
Thanked 0 Times in 0 Posts
94 F250 w/351 startup and idle issues, MAPS?

When starting up my truck, it will die after starting, then will usually puff black smoke, then starts, then it will idle with a rhythmic surging. Then, it will go ok down highway, and settles down. Is this the MAPS sensor?
jlsmith37804 is offline  
Sponsored Links
post #2 of (permalink) Old 11-27-2004, 07:58 PM
Join Date: Apr 2001
Location: eustis , Florida
Posts: 1,444
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 94 F250 w/351 startup and idle issues, MAPS?

Could be, but the surging makes me think of the IABv. If your not getting any codes, i would pull off the air intake hoses to the throttlebody first and check for carbon buildup on the throttle plates. If present, most likely it is also in the *idle air by-pass valve* passages that is mounted to the side of the TB. It needs to be unbolted and cleaned out with carb cleaner the plates can be cleaned with a rag soaked in it. If i would start by looking for a vacuum leak.

also, some earlier 5.8L EFI`S had an issue with oil coming up into the pcv valve and due to the location on the rear of the upper intake plenum, dump oil into #4 cylinder, i would check your pcv system while your at it for excessive oil. the cure is to plug the original hole and relocate the port on the plenum to the middle by tapping a new hole ( pipe thread). just an afterthought though, not necessarily pertaining to your situation.
BRONCOMANIA is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome