5.0 efi on then off throttle dying

Reply Subscribe

Thread Tools

Search this Thread

Apr 19, 2014 | 03:44 AM

swirlparanoid

Thread Starter

New User

Joined: Jun 2010

Posts: 12

Likes: 0

5.0 efi on then off throttle dying

When i give it throttle then let off soon after such as creeping in traffic it will almost die and sometimes will die. Everything seems to be fine except for that. Any ideas?

New iac
new tps
new plugs and wires
tb is clean
Im checking for vac leaks tomorrow although there never has been one

Think the new iac could be bad? Its a Borg-Warner with a lifetime warranty...

Apr 19, 2014 | 07:22 AM

Franklin2

Moderator

Joined: Jan 2001

Posts: 56,948

Likes: 2,717

From: Virginia

What does the engine do when it's warmed up fully and idling, and you unplug the IAC wiring plug?

Apr 19, 2014 | 08:51 AM

ctubutis

Moderator

Joined: Nov 2007

Posts: 22,415

Likes: 92

From: Denver Metro Area, CO

Any computer-controlled engine like this, first diagnostic step is to pull the codes. You can take it to a parts store and they'll do it for free (assuming they know how to deal with something this old) or you can do it yourself at home with a test light or voltmeter:

Ford Ranger - Testing EEC-IV Equipped Engines

Apr 19, 2014 | 03:33 PM

tempest411

Senior User

Joined: Oct 2012

Posts: 497

Likes: 4

Yes, check the computer for trouble codes. My '85 did something like this, and while I couldn't pinpoint the cause, it went away after I replaced the IAC valve, the MAP sensor, and the TPS (making sure the TPS reads .98-.99V with the throttle closed). Also consider these trucks are dinosaurs when it comes to electronics, and so are full of connectors that aren't in very good shape. It would be a good idea to carefully pull them apart, clean them (abrading the contacts with pieces of folded-over fine grit sand paper), and then put them back together.

The 85-86 EFI trucks have to be the worst trucks Ford ever made thanks to flaky electronics. Welcome to my nightmare!