SPONSORED LINKS

Rough running

Tiny
TERESA BISHOP
  • MEMBER
  • 1993 FORD RANGER
  • 4.0L
  • 6 CYL
  • 4WD
  • MANUAL
  • 111,111 MILES
Runs perfect one day and rough the next. Or not at all. Replaced MAF, IAC, TPS, PCV, temperature sending unit, computer, cleaned injectors and replaced rubber seals. Replaced spark plugs, coil pack and bad wires. Replaced throttle body. Checked all vacuum hoses for leaks. Checked fuel pressure at 30 psi. It has a new air filter. This is a different engine. The old engine ran rough to but had to replace because was damaged by water through the air intake.
SPONSORED LINKS
Monday, February 24th, 2020 AT 3:22 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon.

I would start by checking the compression. You have had no success replacing parts so it is time to do some diagnostics to find out the reason.

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/engine-misfires-or-runs-rough.

when you checked the fuel pressure, was it running or off? It should be 35-40 pounds.

Low pressure will cause this issue.

I would also check the fuel pressure regulator. Remove the vacuum line while running and see if any fuel comes out.

Roy

Image (Click to make bigger)
Thumb
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, February 24th, 2020 AT 4:17 PM
Tiny
TERESA BISHOP
  • MEMBER
  • 24 POSTS
If it had low compression would it run perfect and then not? Checked fuel pressure while running. But not sure if gauge works correctly. Replaced fuel regulator.
Was this
answer
helpful?
Yes
No
Monday, February 24th, 2020 AT 5:34 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Yes, still check the compression and recheck the fuel pressure.

Roy
Was this
answer
helpful?
Yes
No
Monday, February 24th, 2020 AT 5:43 PM
Tiny
TERESA BISHOP
  • MEMBER
  • 24 POSTS
Okay, we will check that tomorrow. I'll let you know. Thanks.
Was this
answer
helpful?
Yes
No
Monday, February 24th, 2020 AT 5:49 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

Always glad to help.

Keep us updated.

Roy
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, February 24th, 2020 AT 6:17 PM

Please login or register to post a reply.

Related Engine Runs Rough Content

How to Read Codes
VIDEO
How to Read Codes
Instructional repair video
Check Engine Light
GUIDE
Check Engine Light
Why is my check engine or service engine soon turned on? In this guide we talk about what this is associated with this notorious light, what it is used for and what you...
VIEW MORE

Sponsored links