Dies on cold start unless throttle is applied and bogs on initial acceleration

[jake13]

I am at my wits end, I have replaced near every sensor I can think of on my motor (‘89 5.0) and yet everytime I have to start the car cold it revs up and dies. It will restart immediately and then struggle for a few seconds before dying. Once it finally finds its idle and goes into gear (AOD) it will buck and stumble when the throttle is applied and the car is rolling. I’ve found that if I really hit the throttle and get into second gear the issue goes away and it also goes away once the motor is hot. I don’t have any issues at stop signs or red lights because the motor is warm enough. This all started after getting caught out in a rain storm and a bit of water got into my intake. It fried the MAF sensor and replacing that was all it needed to run again. However, I’ve been having this idle issue since which never happened before. I took it to a shop and they told me the water didn’t make it into the engine and there isn’t any knock or tick. The motor is completely stock except for a “cold” air intake which is just a cone filter hanging out in the engine bay.


Here is everything I’ve done so far:
Cleaned EGR valve
New EGR position sensor
New EGR solenoid
New MAF sensor
New MAP sensor
New spark plugs and wires
New ignition coil
New distributor cap
New ACT sensor
New ECT sensor
New TPS
Replaced PCV screen and cleaned PCV valve
Fixed several vacuum leaks and am 99% sure there’s not any others
Cleaned IAC valve
I’ve also done several base idle resets to no avail

 

[General karthief]

Help me create the "Surging Idle Checklist"

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank...

www.stangnet.com

Read and follow directions,

 

[jake13]

Help me create the "Surging Idle Checklist"

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank...

www.stangnet.com

Read and follow directions,

It’s not necessarily surging but rather stalling

 

[jake13]

You can hear it click or pop in the intake when it tries to die and the motor bucks giving a little power and then none over and over. But the Tach doesn’t move

 

[General karthief]

It covers stalling issues too.

 

[CAMTWO1070]

I am at my wits end, I have replaced near every sensor I can think of on my motor (‘89 5.0) and yet everytime I have to start the car cold it revs up and dies. It will restart immediately and then struggle for a few seconds before dying. Once it finally finds its idle and goes into gear (AOD) it will buck and stumble when the throttle is applied and the car is rolling. I’ve found that if I really hit the throttle and get into second gear the issue goes away and it also goes away once the motor is hot. I don’t have any issues at stop signs or red lights because the motor is warm enough. This all started after getting caught out in a rain storm and a bit of water got into my intake. It fried the MAF sensor and replacing that was all it needed to run again. However, I’ve been having this idle issue since which never happened before. I took it to a shop and they told me the water didn’t make it into the engine and there isn’t any knock or tick. The motor is completely stock except for a “cold” air intake which is just a cone filter hanging out in the engine bay.


Here is everything I’ve done so far:
Cleaned EGR valve
New EGR position sensor
New EGR solenoid
New MAF sensor
New MAP sensor
New spark plugs and wires
New ignition coil
New distributor cap
New ACT sensor
New ECT sensor
New TPS
Replaced PCV screen and cleaned PCV valve
Fixed several vacuum leaks and am 99% sure there’s not any others
Cleaned IAC valve
I’ve also done several base idle resets to no avail

Sounds like you may be having an issue with the AOD selector sensor..When your ECU doesnt sense whether its in Neutral or Park is a pretty conflicting issue for a vehicle with an automatic when the vehicle is going 45mph or registering as being in Drive when in its actually in Park or Neutral as with an automatic the computer has settings for both and it affects idle , fueling and spark advance etc due to there being different spark tables the ECU follows........




In a stickshift this is less of an issue but when you look Ford created an idle issue with the A9L and everyone who bypasses the clutchswitch by connecting it together is running off of the neutral tables and the ones who just disconnect it are always in the drive side unless you have a chip and can make both the exact same...

In a vehicle with an automatic the idle aswell as spark must be manipulated to get a smooth gear selection then be manipulated to adjust to the load of the torque converter at standstill and under load



I had to change these in my tune to match in neutral and drive due to having a stickshift but the ones on the right are stock A9L settings...Even though theyre the same with drive being more comprehensive just pushing the clutch and releasing it gave me a small idle differential when pushed then released until I made both exactly the same...



There are 3 spark tables too and the base is the enhanced table to get the engine up to speed from a dead standstill than switches over to either the sealevel or the altitude table to save the engine from damage from timing thats too far advanced in the lower load areas of the timing table altitude and sealevel timing tables..

 

[Mindseye007]

I am at my wits end, I have replaced near every sensor I can think of on my motor (‘89 5.0) and yet everytime I have to start the car cold it revs up and dies. It will restart immediately and then struggle for a few seconds before dying. Once it finally finds its idle and goes into gear (AOD) it will buck and stumble when the throttle is applied and the car is rolling. I’ve found that if I really hit the throttle and get into second gear the issue goes away and it also goes away once the motor is hot. I don’t have any issues at stop signs or red lights because the motor is warm enough. This all started after getting caught out in a rain storm and a bit of water got into my intake. It fried the MAF sensor and replacing that was all it needed to run again. However, I’ve been having this idle issue since which never happened before. I took it to a shop and they told me the water didn’t make it into the engine and there isn’t any knock or tick. The motor is completely stock except for a “cold” air intake which is just a cone filter hanging out in the engine bay.


Here is everything I’ve done so far:
Cleaned EGR valve
New EGR position sensor
New EGR solenoid
New MAF sensor
New MAP sensor
New spark plugs and wires
New ignition coil
New distributor cap
New ACT sensor
New ECT sensor
New TPS
Replaced PCV screen and cleaned PCV valve
Fixed several vacuum leaks and am 99% sure there’s not any others
Cleaned IAC valve
I’ve also done several base idle resets to no avail

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