1999 Tacoma P0303 misfire

I have a 99 Tacoma 4cyl 2.7L 2WD. I have a P0303 misfire, replaced spark plugs and ignition coil. Next thing was to look at fuel injector. Any other ideas as to what to look at? Engine shake is really rough, RPM are low when it idles. I bought it about a week ago, trying to fix it up, newer to fixing up cars, any advice is greatly appreciated. If I get a new fuel injector, OEM or upgrade it?

 

Worth a compression test-- valves OK?

 

"Search" is your friend. There are many, many, MANY posts in this forum that describe how to test fuel injectors. While in this forum, try searching on something like "bad fuel injectors", or "testing fuel injectors", or "tacoma PO 0300", or "tacoma injector problem", etc.

Here's a thread that you can find on this very page that may get you started:

https://www.tacomaworld.com/threads/2-7l-cylinder-3-misfire.803191/page-3#post-29455264

If you cannot find an answer, then you could also search the entire internet by using the same search terms.

 

I would start with compression test and rule that out first

 

Yeah, just bought mmm, maybe has a known issue.

Compression check is the first place I would start.

How many miles? RZ’s need the valve clearance checked and corrected about every 100k.

 

There is a guy on here who had the same issue… did everything that you should do to diagnose it. He took the injectors to a shop and they passed, he pulled the head and ended up overhauling the motor only to have a miss in #3 after it was all done. The injector was bad from the beginning even after the shop that had the injectors said they were good to go.

 

It's can be alot of this that cuase miss fire. You just have to go step by step start ruling things out