[South69]

Working on a 2004 with the 5 cylinder. Truck has about 275k miles on it. It started to have a terrible misfire when cold. When it warmed up it runs fine.. I been googling and came across a few posts about valve seats being an issue in these engines.

My question is, if it is bad seats.. will the misfire happen even when the truck is warmed up? and will it happen every start or is it intermittent?

Lastly, will a compression test tell me if the seats are bad? Or do i need a leak down tester.

 

[cart7881]

Welcome to the Nation.

Can't answer your valve questions, but have you eliminated all possible external causes? Nothing in your post indicates what has been done to troubleshoot this problem. A bit of background would be helpful. Is the 'check engine' light on? If so, have you scanned the computer to determine which cylinders are misfiring?

 

[South69]

Welcome to the Nation.

Can't answer your valve questions, but have you eliminated all possible external causes? Nothing in your post indicates what has been done to troubleshoot this problem. A bit of background would be helpful. Is the 'check engine' light on? If so, have you scanned the computer to determine which cylinders are misfiring?

yea just got a p0300 i believe it was, random misfire. Replaced all coils and spark plugs and ran great for a few days, then acted up again. That's the extent of repairs at this moment.

 

[cart7881]

You should find a capable scan tool that can read live data from the PCM. It would indicate which cylinders are misfiring, whether random or not.

 

[South69]

You should find a capable scan tool that can read live data from the PCM. It would indicate which cylinders are misfiring, whether random or not.

yea i just have a basic autel $30 cheapie. Any recommendations on a good scanner?

 

[cart7881]

I hesitate to recommend any particular brand of scanner as I only have experience with one. My suggestion would be to look arouind on Amazon and get an idea of what is available, in your price range, and how they are reviewed. Some have free updates, but for most of the upper level tools you would have to purchase updates. Keep in mind free updates are only good if they are actually provided. Also, updates are not required to keep the tool operational.

Launch and Autel are frequently used by YouTubers. I have read good reviews of the Thinkcar brand also. Again, not a recommendation, but this seems to have features that are helpful and not overly expensive:

Amazon.com

Do your research and make sure of the capabilities of whatever you choose.

 

[South69]

So i got around to doing a compression test on the truck. Cylinder #1 had 160psi, Cylinder #2 had 180psi, Cylinder #3 had 170psi, Cylinder #4 had 60psi, Cylinder #5 had 80psi... Guess it has the dreaded valve seat problem... Truck does have 265k miles. Guess off to the scrapyard.

 

[dirtwarrior]

Just have the head rebuilt

 

[Rex Kramer]

I would pour like 50 bucks of seafoam at it before I sent it to the scrapyard, but that's just me.