Do you still have yer old plugs? If yer burning coolant in one or more of the cylinders, the spark plug(s) will be cleaner than the rest as it will have the power of steam cleaning in that cylinder. Snap some piccies of the business end and post them up. Don't fergit to use the macro mode on yer camera. The macro mode indicator should look like a flower.

Is the check engine light on? If so, have you pulled any codes? If you have...what code(s) was/were indicated?

Have you hooked up a computer diagnostics to yer ODBII port yet? It will probably give you more information to go by instead of just taking stabs in the dark.

What kind of plugs did you put in? Post up what brand and model number.

When was the last time you replaced the spark plug wires? Have you measured the resistance on them?

Did you inspect the coil on plug boots, too? Snap some piccies of them and post them up as well.

Have you measured the coolant temp sensor? This is a 2 wire sensor which the ECU uses vs the single wire one the instrument panel uses to show the coolant temp.

Have you measured the TPS? You'll have to cycle the throttle slowly and read the measurement looking fer any drop outs.

 

I was sure someone out there had some ideas, thanks Bam!

I did have a check engine light last summer along with a ticking from one of the coil packs (number 5, I think), passenger side, middle plug.

I pulled the code and it was "misfire on # 5".

I inspected the coils, wires and then pulled the plugs and #5 was really loose. After I tightened it up the noise went away along with the check engine light.

That prompted me to purchase all new plugs (from the dealer) and replace them. All the plugs looked normal except for #5, it was a bit darker than the rest. I assume that was from being loose for some time and heating up.

Since then I have had no check engine light and no ticking sound or problems.

I am out of town for a few weeks right now and cannot take any pictures of the plugs, wires or anything else, sorry....

Other questions you asked:

When was the last time you replaced the spark plug wires? Have you measured the resistance on them? I have not replaced in the 20K miles I have had the truck. They look good, but I realize I should look deeper.

Did you inspect the coil on plug boots, too? Snap some piccies of them and post them up as well. Did not inspect those, I see a different post on that and will read up on that proceedure.

Have you measured the coolant temp sensor? This is a 2 wire sensor which the ECU uses vs the single wire one the instrument panel uses to show the coolant temp. I have not, what should I look for?

Have you measured the TPS? You'll have to cycle the throttle slowly and read the measurement looking fer any drop outs. I have not. I don't have a scan tool so is this best handled by my shop?

Thanks for all the great ideas.

 

Have you measured the TPS? You'll have to cycle the throttle slowly and read the measurement looking fer any drop outs. I have not. I don't have a scan tool so is this best handled by my shop?

You can do it yourself, but I wouldn't jump to that yet.
First off, what does your exhaust look like? If you have a blown HG and are burning coolant, the exhaust will be white and smell sweet. But on a cold morning normal exhaust can look the same way for a few minutes will the vehicle warms up.

The fact that your problem goes away when the engine warms up could mean the problem is in the Cold Start Injector circuit. The injector could be clogged, the CSI relay could be bad, etc.

 

I haven't come across a dedicated cold start injector on the 5vzfe engine...but I know the 3.0L 3vze engine had one.

Another thing is that the MAF sensor may be dirty and could probably use some cleaning with some MAF sensor cleaning spray you can pick up at the auto parts store fer under $10. Just make sure you don't make physical contact with the wire...or you could be buying a used/new one.

 

I have cleaned the throttle body and all looks clean. Would a dirty MAF cause the rough idle and shaking at cold start?

I also have one other clue that may help diagnose the missing coolant....

When ever the heat control is set to the heat position, I hear a gurgling sound coming from behind the dash. This sounds like water (coolant?) bubbling or mixing with air. This only happens with the cabin temperature control in the heat area. When I slide it over to the cold/blue area, the sound goes away.

What causes this? Heater Core? Could this explain the loss of coolant?

 

The MAF tells the ECU how much air is being drawn into the engine and the ECU adjusts accordingly. If the MAF is dirty, the readings can be off enough to where the ECU can't adjust fer. To clean the MAF with MAF sensor cleaner...it's a simple low cost project that you can easily do yerself in about 15 minutes. Just don't fergit to plug the MAF back in...it even happened to me.

The coolant gurgling tells me that there is air being introduced into yer cooling system. It could be from yer heater core. Have you properly burped yer cooling system? Have you isolated the heater core to eliminate it as a possible problem? You can disconnect the heater core and connect the two hoses together using a coupler to isolate the heater core out of the equation.

 

Just thought of another place that might be introducing air/leaking...the heater control valve. It's located in the engine bay in the middle of the firewall.

 

Just an update on this old thread....

After a few tries to self diagnose the problem, I went back to the dealer and the problem was identified as a small leak in the head gasket. Not big enough to cause any signifcant running problems, just a little hesitation at cold start.

I decided to move forward with the repair as I am commited to the T. They pulled the heads and ordered the full gasket set along with a new Timing belt/water pump. The heads were sent to the machine shop for machining and pressure test. Both came back with hairline cracks....After two additional sets failded the pressure test, I was able to find a used set that were acceptable after valve jobs on both of them.

The dealer swapped out the belts and installed the new gaskets along with the rebuilt heads and I am now driving again. $2400

Still cheaper than a new truck and I now have a new top end...

I problably could have waited for the leak to become more severe but I don't like operating that way so I just bit the bullet.

The truck still makes some gurgling sound when the heat is on... Dealer blead the coolant system 2-3 times and was unable to solve.....

 

The truck still makes some gurgling sound when the heat is on... Dealer blead the coolant system 2-3 times and was unable to solve.....

I'd be curious on how they bled the system out. I wonder if they filled the engine passages with coolant before they filled the radiator. You can easily bleed the cooling system yerself...

 

Wow that is a lot of work. Sounds like you did it right for sure! Sorry to hear about all your troubles. At least the shop was a good one and did the repair correctly!

Glad your truck is back up and running!

As for the gurgling. Mine would do it very slightly every so often even several years after the water pump and timing belt were done.

 

Yep, the T is running strong...

As for the gurglaling, I think BAM may be right, perhaps the heater control valve is heading south.

I am planning on trying yet another bleed on the system....

Anyone have any 'best practices"?

 

Replace the coolant temp sensor. It's not giving the ecu the right info and throwing the fuel mixture, cam and timing off.

 

I'm not one fer just replacing parts without testing it or the harness fer issues. I'll fire up the OBDII reader to make sure the engine coolant temp (ECT) sensor is reporting the correct temp first.