Strange Idle issue

Reply Subscribe

Thread Tools

Search this Thread

Jun 16, 2015 | 02:10 PM

The Krustinator

Thread Starter

8th Gear

Joined: Jun 2015

Posts: 8

Likes: 0

Strange Idle issue

Have a 2003 F-250 with 174,000 miles. Recently replaced CPS and ICP and it's running much better. It normally idles at about 700 rpm. Lately, after driving for any distance above ~40mph, when I come to a stop, the rpm won't drop below about 850 rpm. If I shift to neutral (automatic trans), the idle drops to around 700. At the next stop sign/light, it's back up to around 850.

Any suggestions?

Thanks

Jun 16, 2015 | 02:17 PM

Whitey Ford

FTE-Spread The Knowledge

Joined: Feb 2008

Posts: 2,285

Likes: 240

Were they OEM parts?

Jun 16, 2015 | 04:13 PM

The Krustinator

Thread Starter

8th Gear

Joined: Jun 2015

Posts: 8

Likes: 0

The CPS was put in by the local Ford shop. The ICP I got off Amazon and installed it myself.

Jun 16, 2015 | 04:57 PM

Whitey Ford

FTE-Spread The Knowledge

Joined: Feb 2008

Posts: 2,285

Likes: 240

Do you have a scan tool that you can monitor with? What issues were you having that lead you to change CPS and ICP?

Jun 16, 2015 | 05:44 PM

The Krustinator

Thread Starter

8th Gear

Joined: Jun 2015

Posts: 8

Likes: 0

Don't have a scan tool. Looking around for one.

The symptoms were the classic ones, rough idle, stalling a low speeds, surging on the highway. All of those went away after the ICP change.

Jun 17, 2015 | 08:11 AM

Whitey Ford

FTE-Spread The Knowledge

Joined: Feb 2008

Posts: 2,285

Likes: 240

Where are you located? Maybe someone with an AE here is close to you and can do some live monitoring. Most of the time AE will point you in the direction of the problem without wasting your time and money.

Jun 17, 2015 | 12:48 PM

The Krustinator

Thread Starter

8th Gear

Joined: Jun 2015

Posts: 8

Likes: 0

I live in Covington LA. I have been looking around for an AE. Supposedly there is a good shop over in Amite.

Top 10 Ford Truck Tragedies

Joe Kucinski

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

Brett Foote

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Michael S. Palmer

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Verdad Gallardo

10 Best Ford Truck Engines We Miss the Most!

Joe Kucinski

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Brett Foote

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Michael S. Palmer

10 Most Surprising 2026 Ford Truck Features!

Joe Kucinski

Top 10 Ford Trucks Coming to Mecum Indy 2026

Brett Foote

5 Best / 5 Worst Ford Truck Wheels of All Time

Joe Kucinski

Jun 17, 2015 | 01:24 PM

Whitey Ford

FTE-Spread The Knowledge

Joined: Feb 2008

Posts: 2,285

Likes: 240

You can get AE from Riffraff Diesel for the cheapest I've seen. It will save you big money on this issue and future issues. 1 trip to a shop will cover it's cost, most of the time.

Jun 19, 2015 | 06:14 AM

#10

The Krustinator

Thread Starter

8th Gear

Joined: Jun 2015

Posts: 8

Likes: 0

While I hunt for an AE, could this be a transmission sensor issue?

Jun 19, 2015 | 07:14 AM

#11

Whitey Ford

FTE-Spread The Knowledge

Joined: Feb 2008

Posts: 2,285

Likes: 240

The AE would tell you if it was. If you didn't have the issue before you changed CPS and ICP, that is where I would start. The reason I asked if they were both OEM is because aftermarket sensors have a bad reputation of causing new problems.

Jun 19, 2015 | 10:44 PM

#12

Mohawkwoodman

New User

Joined: Jun 2015

Posts: 9

Likes: 0

Icp solenoid should be verified and looked over with a scan tool to see the actual running pressure 500-700 should be normal, then get that verified by swapping the icp sensor with a mechanical guage. Hows the oil and is the air filter breathing or is it the classic air starved diesal that runs poor? Ive seen a few that never start due to choked air filters.