Never ending idling problems

[kxri318]

My truck has been idling really rough since I got it, I've replaced just about every single sensor there is on this truck except for the TPS. After replacing all that, I decided to test for vacuum leaks and I saw a leak from the lower intake manifold gasket and the pcv valve. Replaced both gaskets and the breather gasket on the right too, now it runs even worse. Both then and now, it runs so rough the engine shakes bad at random times. I'm not even 100% sure how to set the timing because there's a hole but also an almost arrow looking metal piece pointing on the markings on the harmonic balancer so I'm not sure if the timing is right. It idle surged rarely before, but now its an extremely bad idle surge to the point where I have to hold the brakes to stop myself from slamming into the back of the garage. It's also varying the RPMs all over the place as it feels like. It would idle high but then go down to the point where its struggling to stay running without me touching the gas pedal at all. I've been fighting this truck for the past year and I'm so sick of it. I can't figure out what's causing these things.

 

[franklin2]

I assume it's the 1986 2.9 v6 since you are in this forum? Have you pulled the computer codes yet? Do you have a timing light?

 

[rusty ol ranger]

Have you pulled codes?

Does it run ok besides idle?

When you set the timing did you pull the SPOUT connector?

 

[kxri318]

I assume it's the 1986 2.9 v6 since you are in this forum? Have you pulled the computer codes yet? Do you have a timing light?

Absolutely no codes, had a timing light when I set the timing before I pulled it apart and used that to set it. Still ran bad then. Now my timing light is broken so I set it to TDC and turned it to when it ran the least horribly.

 

[kxri318]

Have you pulled codes?

Does it run ok besides idle?

When you set the timing did you pull the SPOUT connector?

No codes at all. It runs slightly less horrible when at higher rpms but still misfires (I think...??). I took out the spout when I did the timing.

 

[rusty ol ranger]

No codes at all. It runs slightly less horrible when at higher rpms but still misfires (I think...??). I took out the spout when I did the timing.

Check fuel pressure and run a compression check

 

[kxri318]

Check fuel pressure and run a compression check

I can try to check that. I'd have to buy the tools to do it though.

Here's a video of the engine shake and the exhaust so you can more easily hear how its running.

Engine Bay Video:

Exhaust Video: https://youtube.com/shorts/v-WO-b1SWWo

It gets worse as it warms up

 

[rusty ol ranger]

I can try to check that. I'd have to buy the tools to do it though.

Here's a video of the engine shake and the exhaust so you can more easily hear how its running.

Engine Bay Video:

Exhaust Video: https://youtube.com/shorts/v-WO-b1SWWo

It gets worse as it warms up

Thats the cleanest 2.9 ive seen in a long time.

Pull your vacuum hose off the fuel pressure regulator and see if there is fuel in it. It could be a bad regulator.

I believe autozone rents compression and fuel testers.

It could be a coolant temp sensor but that should pop off a code.

 

[kxri318]

Thats the cleanest 2.9 ive seen in a long time.

Pull your vacuum hose off the fuel pressure regulator and see if there is fuel in it. It could be a bad regulator.

I believe autozone rents compression and fuel testers.

It could be a coolant temp sensor but that should pop off a code.

Yeah I see my autozone rents those out. I didn't even know they rented tools until now. Anyway, the fuel regulator is brand new along with the coolant temp sensor too. Not sure where the issue originates but my temp gauge reads overheating all the time. Weirdly, before I replaced the coolant temp sensor it read lower than it should but still worked (and ran just as bad)

 

[rusty ol ranger]

Yeah I see my autozone rents those out. I didn't even know they rented tools until now. Anyway, the fuel regulator is brand new along with the coolant temp sensor too. Not sure where the issue originates but my temp gauge reads overheating all the time. Weirdly, before I replaced the coolant temp sensor it read lower than it should but still worked (and ran just as bad)

Theres a coolant temp SENDER (1 wire, runs gauge only)

and SENSOR (gives info to ECM, 2 wire)

Did you replace the one wired one?

Also if its pegged on hot chances are the wires grounding out to the sender.

 

[kxri318]

Theres a coolant temp SENDER (1 wire, runs gauge only)

and SENSOR (gives info to ECM, 2 wire)

Did you replace the one wired one?

Also if its pegged on hot chances are the wires grounding out to the sender.

Sorry I've replaced so many different senders and sensors on this thing I forgot. Sender and sensor are both brand new. It goes up and down slightly still even though its at the top of the gauge, but doesn't move significantly. It did the same thing with the old *sender*, it just did that at a lower temp reading.

 

[rusty ol ranger]

Sorry I've replaced so many different senders and sensors on this thing I forgot. Sender and sensor are both brand new. It goes up and down slightly still even though its at the top of the gauge, but doesn't move significantly. It did the same thing with the old *sender*, it just did that at a lower temp reading.

Its not actually getting hot is it? 2.9s and heat dont mix

 

[kxri318]

Its not actually getting hot is it? 2.9s and heat dont mix

I doubt it. It said it was overheating while the radiator was still cold.

 

[franklin2]

Absolutely no codes, had a timing light when I set the timing before I pulled it apart and used that to set it. Still ran bad then. Now my timing light is broken so I set it to TDC and turned it to when it ran the least horribly.

Not a very good way to set the timing. Harbor Freight has the timing light for $31.00. If everything is correct, you should have gotten some codes. Looks like your code reader is not working.

 

[Shran]

Not a very good way to set the timing. Harbor Freight has the timing light for $31.00. If everything is correct, you should have gotten some codes. Looks like your code reader is not working.

Ahh the old "turn it till it's hard to start, back it off and that's where it should be." I love that one. I just messed with the distributor on my 302 and noted a significant difference in how it runs at 12 BTC vs 10 BTC... that is a tiny amount... that will DEFINITELY affect idle speed!