Runs rough the fine, no codes

[Vikingmetalfab]

My 99 3.0 manual 4x4 is doing the ereader rough cold start. I know someone will jump on me for not searching but truth is I've been fighting this for months and have read every thread I can find here and on other sites that even remotely looks plausible. That being said.

Truck is a 99 3.0 non flex with a manual and 4x4. It has roughly 250000 miles on it.

When i go to start it in the morning (temp doesn't seem to matter) It will die 4 times like clockwork before it will idle. Idles rough for a few minutes and then runs great. If it has been sitting about an hour this process is reapeated. If less time then there are no issues.

I've pulled the codes a dozen time with a good code puller and never have any useful codes. Usually no codes at all. Also no check engine light ever. I've replaced all gaskets from the head gaskets up. Verified no vacuum leaks, replaced all three o2 sensors, replaced IACV, tested the egr system cleaned the maf and all sensors, changed fuel filter and oil, new battery and alternator and ran a can of seafoam.

Any ideas?

 

[mnosekabel]

I'm going through a very similar situation. please let me know of you find anything!

 

[RonD]

You say "When i go to start it in the morning (temp doesn't seem to matter), It will die 4 times like clockwork before it will idle"

So engine can be fully warmed up in the morning, and still stalls when you "restart it"?

Or

When you start the cold engine it stalls a few times until engine/coolant warms up?

All engines need to be "Choked" when cold, not a "carburetor thing"
With fuel injection the computer uses the ECT(engine coolant temp) sensor to operate the electronic Choke, which basically means Rich fuel mix, high idle and advanced spark timing.
Computer watches ECT temp and slowly removes the Choke as engine/coolant warms up.
Without a Choke a cold engine won't stay running until it warms up.(its a gasoline vapor thing)
ECT sensor is not related to dash temp gauge, just FYI.

Choke mode is also Open Loop, and you could have a computer issue
The Computer needs Feedback from the O2 sensors so it can adjust air/fuel mix on the fly
But O2 sensors can't work until they are heated up above 650degF, which is why they are "Heated O2 sensors"

So computer runs in Open Loop, and uses preset air/fuel mixes in memory, while it waits for O2 sensors to warm up
This is also Choke mode if engine was stone cold, but if its just a restart after 5 to 20 minutes then just Open Loop until O2s get nice and HOT again

When O2 sensors are HOT computer switches to Closed Loop, "closed" because it now has feedback from the O2s

Your description suggests there is a problem with Open loop and it goes away in Closed Loop

If you can get a live data reader, they are $30, you could watch what the computer is seeing on Cold Start, i.e. the ECT temp, see if ECT is working as it should.


"New" parts...............................
New used to mean "tested and working"
New now means "You test it and we will replace it if it doesn't work"

So grain of salt when installing "new" parts, assume they DO NOT WORK, not that they do work
Volt/OHM meter is your best friend with any vehicle made after 1985

 

[Vikingmetalfab]

Temp doesn't matter in ambient temperature. It did this in the winter in negative temperatures and does it now when its 60 degrees in the morning or 85 in the afternoon.

New parts as untested iacv and it was dead. New one works fine but didn't fix anything. The o2 sensors were replaced with new ones just because they were the original ones and it seemed like a good possibility. Batt and alt were were both going out also.

 

[RonD]

I would install a new ECT sensor then, they are not too expensive

Picture here: https://www.ranger-forums.com/attachments/general-technical-electrical-18/68679d1416398152-coolant-temp-sensor-issues-coolant-sensor.jpg

On the left is the SENDER, for the dash temp gauge, usually 1 wire
On the right is the ECT SENSOR, always 2 wires

In the center is the thermostat housing and upper rad hose

 

[Dirtman]

Usually no codes at all

What does this mean? Are there codes or not...