2005 Dodge Dakota 4.7 Shaky Idle when warmed up (No CEL)

463 Views 17 Replies 8 Participants Last post by elitescouter, 19 d ago

elitescouter

Discussion Starter · 28 d ago

I just bought my 2005 Dodge Dakota 4.7 couple months ago and I have been going through it to make it a little reliable truck when I need to haul stuff in the bed.

I am noticing somewhat of a rough idle after the truck comes up to warm temps, before that it idles fine. The truck doesn't throw any CEL's or stall, I can just feel it when sitting at a light (regardless if in drive or neutral). I have done the following since I got the truck few months ago.

Changed Oil/Filter
Flushed Coolant
Replaced Sparkplugs (NGK V-Power Copper top, gapped to 0.040)
Replaced Evap Solenoid
Seafoam cleaning through intake.
Fully cleaned throttlebody.
Smoke Tested (No leaks detected)
Replaced EGR Valve

Other than the idle, truck seems to run fine at WOT and gets up to speed easy.

The only thing that I am noticing is that on 02 Bank 1 Sensor 1, it looks very jaggedy while 02 on Bank 2 Sensor 1 looks smooth. Here is the picture.

Could I have a 02 Sensor that is going out?

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elitescouter

Discussion Starter · #4 · 28 d ago (Edited)

oldmarine said:
You shouldn't compare graphs from two different scopes/scanners. In any case, both of those pictures show they are for Bank 1 Sensor 1 (which is why you shouldn't compare between two different tools).

What do your short term and long term fuel trims look like (both banks) at idle? If they are running rich, you may have an injector issue.

I know that, the bottom graph is a demonstration what it should look like (kind of like a template). The top is very jagged, when I check my other Bank 2 Sensor 1, it's smooth.

I will check tomorrow and post.

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elitescouter

Discussion Starter · #5 · 23 d ago

oldmarine said:
You shouldn't compare graphs from two different scopes/scanners. In any case, both of those pictures show they are for Bank 1 Sensor 1 (which is why you shouldn't compare between two different tools).

What do your short term and long term fuel trims look like (both banks) at idle? If they are running rich, you may have an injector issue.

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elitescouter

Discussion Starter · #6 · 21 d ago

Today I have completely removed throttle body, cleaned it really well and replaced the seal. I have replaced the IAC. I have taken out all the spark plugs on bank 1 and coils and made sure the gap didn't change (0.40) and used electronic cleaner on connectors/coils.

The truck still idles rough, it drives just fine, has power and doesn't stall. The idle is bumpy and it's driving me nuts!

I purchased a injector pulser/cleaner, I am going to start with Bank 1 injectors and clean them to see if anything improves.

I was also wrong on the whole hot/cold rough idle, it just idles rough regardless of cold/hot engine (Almost as if it's getting worse and worse as days go by).

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elitescouter

Discussion Starter · #8 · 21 d ago

Richard D said:
What are your long-term fuel trims? I noticed you posted short-term but these re-learn trims and can be misleading. Long-term should remain steady and tell us if you have a lean or rich condition. I realize you don't have a CEL but let's make sure it isn't another problem.

Good luck and keep us posted.

I will get those today when I drive it home. I did leave the battery disconnected all night to reset any learning. This morning on first start up after battery being disconnected, it was ok. After 10~ mins of idle, it came back.

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elitescouter

Discussion Starter · #11 · 20 d ago

Richard D said:
Interesting data point; cars at startup, cold, are rich by design, at about the time it reaches normal operating temperature fuel normalizes to the famous 14.7:1 air to fuel ratio. If the truck seems fine cold, and rough idle returns at operating temperature, we very well may have a fuel trim issue. Assuming this is correct - the fuel trim readings cold and hot - might reveal in which direction to go. Keep us posted.

I just checked long-term fuel trims and they are flat on both banks.

When I check the timing at idle, it just bounces between 10-18, it's super sparatic. Giving it any throttle or keeping the idle up keeps it steady. It's just super puzzling. Not sure what else to check besides maybe swapping one of the lower o2 sensors and putting it on Bank 1 upper since the 2 upstream sensors and the lower right are the same. Take the lower right and swap it into upper bank 1. It drives fine, it's just the idle that bothers me.

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elitescouter

Discussion Starter · #12 · 20 d ago

Probably when I first got it, I pressure washed the engine bay, maybe something got wet and corroded that didn't have a good seal.

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elitescouter

Discussion Starter · #16 · 20 d ago

Replaced the upstream bank 1 o2 sensor with a denso, same issue. (Also was a pain in the rear to get out).

Took off all the connectors from the ECU and used electronic cleaner. The ground on the ECU was loose, fixed that.

Drove it, felt fine and then after a couple mins of sitting, bumpy idle came back.

I will say, replacing everything I have replaced so far... the truck gets up and goes, so I definitely made the truck run overall better (When I first got it, I was 100% certain my old v6 ranger had more power) but that is no longer true, it's barely keeping traction in 1st and 2nd.

So my journey continues on, I will take a look at the crank sensor and see how hard it's to replace and just replace it since I pretty much replaced 80% of sensors/solenoids so far.

I still need to clean the injectors, my new o-rings are going to show up on the weekend.

The good news is, I will have a peace of mind not guessing when the last owner replaced what, now I know at least what I have replaced so far.

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elitescouter

Discussion Starter · #18 · 19 d ago

Richard D said:
Does flat mean zero, or there abouts?

Yes, Zero.

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