Rough Start after Sitting for A Week

I recently changed my brakes on my Tacoma and ordered the wrong pads so I had to let it sit for a week before I got new pads and could install them. After the install, I went to start the truck for a test drive and it ran rough for 10-15 seconds and was shaking. It made a slight popping noise as well. After that it cleared and ran normal. No codes. This is not the first time this has happened. It usually has to sit for 3+ days for it to happen. Truck has ~175,000 miles and has been supercharged for 50k. No other issues. I maintain the truck very well and recently did a tune up (plugs, filters, oil, cleaned intake, TB, MAF, etc.) Any ideas?

 

My truck starts like it's running on 1 cyl almost every morning. Had a 3.4 that did the same thing. Once warm, never an issue. Always that first start just for couple seconds. Has never given me any issues. I may just need to do plugs and wires.

 

Yea I've found similar threads and seems like other have similar issues. Just strange that it starts fine if I drive it at least every other day. I'm just worried there is some extent of damage being done every time it starts like that, and my motor will be done soon.

Other notes: It does seem to burn oil some. I have to add to it every now and then to keep it from dropping below the low mark. I was thinking maybe a small head gasket leak but the coolant looks fine and doesn't seem to be disappearing. Perhaps it gets some condensation in the fuel lines after it sits for a while. Idk.

 

You may have a weak coil or coils. If I remember right (I mainly work on diesels so this old knowledge has gone to the wayside) its harder on your spark plug and coil to fire when cold. Its easier at op temp so that would be why it goes away after a few seconds.

Given that it also had a popping noise, it could be a lifter bleeding down over time. This can cause a popping noise as you will still have pressure in the cylinder when the other valve opens. For example, lets say your exhaust lifter completely collapsed and your exhaust valve was closing too early. You'd have a bit of compressed exhaust gasses still present when the intake valve opened. This would cause a popping noise out of the intake as the pressure from the cylinder released out of the intake.

Or, you could have some worn rings. I'm not sure about Toyota motors, but some Ford engines are designed with slightly ovular pistons. This miss shaped piston allows for expansion as it gets hot. Basically, with ring wear, it becomes "normal" to have a little bit of blow-by until the piston expands and forces the rings to seal better.

 

Wonder if valve stem seals are leaking oil into the cyl. or an injector bleeding down over a couple of days.

 

Interesting my truck can sit for a week or longer starts right up

Might be any number of things causing the problem

Which seem to have been mentioned

Fouled plugs or fuel system losing pressure along with a fuel filter due to be changed

 

Plugs are brand new (2k), plug wires are fairly new, fuel filter is new (2k), basically entire fuel system is new other than injectors, from when I was chasing down a long hot start issue (pump/regulator fixed it). Everything's pretty new as I said I maintain the truck very well. This is what has me stumped and makes me believe it's something more than tune up issues.

 

Injectors can be tested.

And rebuilt.

 

The real question is when did this problem first start ??

Left over from your Hot Start problem??

 

And really the popping noise almost has to be Ign.

Did you replace the boots under the coils?

If you don't see smoke on start up, the oil burning may just be something to live with.

 

Not left over. This is a new issue that started a few months ago.

 

I'm starting to think it may be an early sign of a leaking head gasket.

Any thoughts?

 

something leaking but I wouldn't think HG.
Are you losing water too?

You're coil boots are new?

 

How bad is the oil on start up?

 

No. Never been replaced from what I know.

 

As in is it burning oil during startup?

 

Sticky valve?

 

I had exactly the same problem after not starting my truck for a week. It did it twice and it never happened again. 1st gen and same engine as you. Sub'd for ideas.

 

Change those boots. they're just short spark plug wires.
You shut off a hot engine and moisture collects in there. Just condensate. A crack in the boot lets in a little of that moisture. you start it and it runs rough 'til that burns off.
Or injector(s) leaking down......but the boots should have been changed by now. They're rubber, they're old and they're subjected to a bit of heat.
Toyotas don't have lifters.

 

How old is the battery? Check voltage when cranking.