Truck is running really bad... Misfire...

Well I ended up taking the truck in, the next steps were a little outa my reach... So took it in, they did a compression test on cyl. 4 and it came out fine, and was getting full compression. I'm not sure what that rules out, i'm assuming it would be a bad gasket if it failed, but anyways the next steps are performing a leakdown, pulling valve cover, checking valves/springs/cam/ not to sure, thats why its in the shop. Anyone have any ideas so far after the compression test passed.

Thanks,
Dan

 

Had same situation on my 03 Tacoma 4cyl. Happened a couple of times and engine light came on....Dealer at first said couldn't get much from the code....Third time went back and the mechanic said it was plugs and could use a fuel injector cleaning. Had them replace the plugs and do the injector cleaning. Never had another problem.

 

Great... well as for injector cleaner, its probably had about 3 cleaners run through it. Sea Foam in the tank, the oil, and through the vac line (3 times). I guess the injector could have gone bad, but it should be fairly clean.

 

You've pretty much replaced everything that could be the issue other than the injector. Try replacing the injector and see what happens. You could probably replace the injector by your self.

 

You can pick up a reman for about 45 and a new injector for about 115.

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1357589&parttype=6224&a=FRc1357589k932792


Another option would be to have a shop run a full strength injector cleaner through the injectors. This involves hooking the fuel system up to a machine that recycles the fuel coming from the pump to the tank and runs a potent cleaner through the injectors.

 

I was looking up some symptoms of a clogged injector. My question is why would the truck run fine cold, run fine until i turn it off and then run poorly till the next time it cools down. If an injector was bad or even clogged wouldn't the truck be running bad most of the time, cold or warm...?

 

It could be the temperature sensor for the EFI. It sounds like the truck works fine when cold and at normal operating temperatures, but when restarting at a temperature in bewteen it is not running correctly. I am not sure if the sensor can be tested, or if it is a replace and see if it helps.

http://www.foreigncarpartsonline.co...on&subcatid=C6020@@Water+Temp.+Sensor&mode=PA

 

Never thought about that, something I look into...

But I picked the truck up today after a week in the shop. Nothing was diagnosed, and they couldn't figure the problem out. Anyone think a toyota shop would be a better idea, or...?

 

My tacoma did the same thing about three months ago, i got it diagnosed and it was a 4th cylinder miss fire. Changed the spark plugs and coils and that did the trick so i dont have a clue if that didnt work...

 

How did u fix yours or did u ever fix yours? It colds starts fine thn let it sit after it warms up it only runs on five cylinders checked coils plugs and wires new o2 sensor and recently installed cold air in take please help!

 

I believe it was a fuel injector. Ended up fixing it and about 4 months later bought a new truck.

 

Everything is eroking fine electrical plugs wires and coils got a new fuel filter boutbto put on wanted to knock the cheap stuff out the way first injector is next tho thanks