1991 Mercury Cougar LS, 3.8 4FACTORY OEM SERVICE PROCEDURE

V8 Ignition Timing

NOTE: Ignition timing is not adjustable on models with DIS or EDIS.
V8 BASE IGNITION TIMING

Application Degrees BTDC @ RPM
5.0L PFI
Auto.Trans. 10 @ 575-725
Man.Trans. 10 @ 625-775
5.8L 2-Bbl. 14 @ 600
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.