What causes idle surge on a fox mustang?

The MAF measures the mass of air going into the engine, measuring this helps compensate for air density changes with altitude and even the weather. Try and avoid an open-air filter element in the engine bay, it has been known to cause surging issues on some Fox Mustangs.

What makes a Ford Mustang Run too rough?

They deal with super hot exhaust that can cover them in deposits that can leave them ineffective. The heat of the exhaust can also bake the wiring going to/from them over time. If an oxygen sensor goes bad, it can make your Mustang run too lean (or rich). A super lean running engine will often idle rough.

Why are the spark plugs on my Ford Mustang not working?

Spark Plugs – One of the absolute most common causes (if not the most common reason that your Mustang may be misfiring) is the spark plugs. Although most modern vehicles use iridium spark plugs, they still need to be changed at the manufacturers recommended interval.

Can a bad spark plug cause a rough idle?

Spark Plug Wires – While not every model and engine combination of vehicles today comes with spark plug wires (a lot are now coil on plug), if your Mustang happens to have them, they can go bad and cause a rough idle. Here’s a great video on how to diagnose bad plug wires with a multimeter.

What causes idle surge problems on Foxbody 5.0?

Low voltage (below 13.2v required to keep the battery charged) can cause a plethora of problems. Underdrive pulleys may also aggravate the situation. Note: If you have a 3G upgrade, be sure you have a ground upgrade (4GA min.) from the block to the chassis.

How does poor fuel delivery cause surging idle?

Poor fuel delivery will cause severe problems including surging idle. The salt/pepper shaker connections are used from the factory to speed up the process of manufacturing, they only had ONE job.

Are there any problems with the fox mustang?

Fox Mustangs come with a lot of hard plastic vacuum lines that will crack with age. It’s always a good idea to check all vacuum lines and replace broken pieces. The Carbon canister is often a culprit of vacuum leaks. Note: Some people recommend using things like carb cleaner to check for leaks (engine will speed up).

Poor fuel delivery will cause severe problems including surging idle. The salt/pepper shaker connections are used from the factory to speed up the process of manufacturing, they only had ONE job.

What should voltage reading be for idle surge?

If the engine is running and there’s no voltage, you have bad wiring or connections. Measure the voltage between the red and blue/light-blue wires. You should see a reading between 0.5 volts to 12 volts (computer is turning on and off quickly, not varying the voltage). Without that reading, you may have bad wiring or connections.

What are the common problems with Foxbody idle surge?

Be sure you don’t have a clogged fuel filter, dirty fuel pump sock (or underperforming fuel pump) or even damaged fuel lines. Poor fuel delivery will cause severe problems including surging idle. The salt/pepper shaker connections are used from the factory to speed up the process of manufacturing, they only had ONE job.

What should idle voltage be on Foxbody 5.0?

Measure the MAF output at the C & D pins on the MAF connector (dark-blue/orange and tan/light-blue wires). Measure voltage across the pins, not between pins and ground! You should see around 0.6v at idle.

How do you set the idle speed on a Mustang?

Set idle using throttle stop. Idle speed will vary depending upon modifications made to the engine. Set to where you are comfortable with idle speed. Set TPS (Throttle Position Sensor) anywhere from .96 to .98 volts. This is done by loosening the mounting screws, and lightly rotating TPS.

Why does my Ford Mustang die at idle?

The car died every time it came to a stop. After driving it with this no idle situation for 50 miles or so, the engine would idle with a surging idle. I ordered the idle bleed plate and installed this and reset the TPS to .98V at idle and followed the directions in the kit about setting the throttle stop.

Where are the 10 pins on a Mustang?

10 pins are little black and white trashcan looking deals mounted on the back of the intake. They should be visible because they arem mounted on a bracket that fits underneath the 5.0 decorative plate on the intake. You may actually have 4 instead of 2 because there was a recall to lenghten the harness.

What is an example of a high idle?

Example: You pull up in the driveway or to a stop light with the clutch in and the car idles it self up to 2K or 3K rpms and then stays there, then finaly drops down when it wants to. Or, your driving down the road, push the clutch in, and the car stays at whatever rpm you were at when you went to make the shift for more than a sec or two.

When does an idle air control valve malfunction?

As soon as you start your car, the idle air control valve will immediately malfunction. If you happen to be away from home and this happens, the stalling will happen every couple of minutes in the beginning. You should be able to make it to the nearest mechanic in time before the engine stalls completely.

What causes the idle speed to go up or down?

If the valve fails or has any issues, it can cause the idle speed to be thrown off. This may result in an unusually high or low idle speed; or in some cases a surging idle speed that repeatedly climbs and falls.

What is the idle motor on a Mustang?

What this series of articles is aimed at is how to fix the most common idle problems found in the Mustang. The fuel injected Mustang uses a small motor/valve assembly that allows a specific amount of air to enter the engine to control it’s idle. This valve is comonly called the idle motor, the IAC (idle air control) or the IAB (Idle air bypass).

How does the fuel injected Mustang engine work?

The fuel injected Mustang uses a small motor/valve assembly that allows a specific amount of air to enter the engine to control it’s idle. This valve is comonly called the idle motor, the IAC (idle air control) or the IAB (Idle air bypass). When your car is new the IAC works remarkably well.

Why is my IAC valve not working on my Mustang?

The problem arises when the car gets some miles on it (usually 75K+) and carbon fouling takes its toll. What happens is dirt, excess air filter oil, and most notably carbon gunks up the IAC valve and doesn’t allow it to either open or close properly.

What should O2 reading be for idle surge?

Use pin 29 (left O2) or pin 43 (right O2) and the ground next to the computer ground. The individual O2 sensor should read between 0.20 to 0.90v at idle. The computer will throw codes 41 and/or 91 for possible O2 sensor failures.

Why does my Mustang hesitate when I put on a load?

But it seems like in any gear when you press the accel down, it will buck or hesitate or stumble. Noticed this morning that it actually drove good while still cold, then as soon as the temp starting to rise up, it started hesitating when a load was put on it. Once warm, it has NO issues starting back up.

How do you positive stop a Ford Mustang?

Positive stop – obtain an old spark plug for the Ford engine – most of us have at least one laying around. Put it in your vice, and with a tool of destruction you deem appropriate – cut off the ground tip and bust up the ceramic around the center electrode.

Why are my vacuum lines breaking on my fox mustang?

Often forgotten but important to check. Fox Mustangs come with a lot of hard plastic vacuum lines that will crack with age. It’s always a good idea to check all vacuum lines and replace broken pieces. The Carbon canister is often a culprit of vacuum leaks.

Why is my Mustang GT Coyote engine not working?

It’s possible this liner is causing minor clearance issues which ultimately lead to the piston lightly slapping up against the cylinder wall. Some owners have had their engines replaced due to scoring on the cylinder walls, which would support this theory.

How long does a Ford Mustang engine last?

First, there seem to be different variations of engine tick. Ford engines have long experienced ticking noises. Often, it seems this doesn’t have any real or noticeable impacts on engine longevity. Some Ford engines tick most of their lives, but still live to see 200,000+ miles.

What are the most common Coyote 5.0 engine problems?

Some of it comes down to how the car is maintained, driven, etc. Some of it simply comes down to the luck of the draw. Moving on, the four most common Coyote 5.0 problems you may hear about include engine tick, auto trans problems, oil pan gasket leaks, and interior rattling.

Do you need to replace the fan clutch on a Mustang?

Inspect all the fan blades for cracks and damage. Do not forget to check the fan clutch for signs of leaking. Any signs of residue on the fan clutch means it needs to be replaced. The fan and fan clutch setup does have it’s limitations. It does rob some power from your engine because it is driven by your engine’s accessory system.

What should I do if I have a cooling problem on my Mustang?

When it comes to maintenance on your factory cooling fan, make sure the shroud is in place and fully intact. Inspect all the fan blades for cracks and damage. Do not forget to check the fan clutch for signs of leaking. Any signs of residue on the fan clutch means it needs to be replaced. The fan and fan clutch setup does have it’s limitations.

Why does the Ford Mustang break down so often?

This is probably due to the fact that people like to drive their pony fast, the faster the better. The owners are used to dogging out their cars, probably because most models of Mustang break down so often and depreciate so fast it really doesn’t matter.

Why does my Ford Mustang make a noise?

If you own a Mustang, that is. The rather embarrassing noise could be caused by a multitude of issues, including worn shocks or struts, damage to tie rod ends, or even suspension bushings. It’s just one of those symptoms that doesn’t easily go away, especially if you happen to live in the North or any Midwestern states.

What’s the problem with my 2005 Ford Mustang?

This is especially true for 2005-2009 model Mustangs. Most sites say the cause is most likely the fan blower resistor. It’s a pretty simple fix, but it also seems to be more of an inherent problem for the car, so it’s something you’ll want to remember testing out when you are test driving one around town.

What kind of engine was in a 1976 Mustang?

The engine bay was re-engineered to accept this updated 302 V8 option for the 1975 model year, with revised hood and header panel. The engine was limited to a two-barrel carburetor and 140 hp. In 1979, it was stopped and came back in 1982 with the moniker of 5.0L.

What was the life of a Ford 302?

The 302’s life cycle lasted from 1968 to 1973. In 1974 due to the Federal government’s rules driven by an oil shortage, Ford no longer offered the V8 powerhouse in the Mustang. However, for reasons unknown to consumers an anemic 302 was offered again in 1975 through 1978.

What causes idle surge on a fox mustang?