I just bought a 1992 Toyota 4runner V6 SR5 and I have this problem with it in the morning when its cold it will start up real rough like its flooded or something then like 3 seconds later it starts idling normally and doesnt have a problem until the next morning when it does the same thing all over again. Its not using any water, theres no water in the oil and no smoke of any kind coming out the exhaust. Any help would be greatly appreciated.[B]

 

Maybe bad valve, or vacuum leak. Just a thought. Mine does it sometimes, with light smoke out the exhaust. Run some injector cleaner through your next gas tank full.

 

Fuel Filter?

 

I ran two tanks of fuel through it (didnt take long with the great gas mileage of the 3.0 ): with fuel injector cleaner and ran some seafoam through the vacuum line. I checked for a vaccum leak by pulling the brake vacuum canister line an hour or two after I turned it off and it had plenty of pressure still in there. What else could it be?? Could it be a pcv valve or maybe a Cold Start Injector??

Thanks

 

Ohh yea and it does seem to idle a bit rough at all times not horrible just a little. Maybe O2 sensor??? I have no clue

 

Usually the O2 sensor is ignored by the ECU until the engine warms up a bit. I would look at the cold start system on the engine, likely a sensor or a cold start fuel injector may not be working right. A Factory Service Manual would have the diagnostic information.

 

I think it may be running a little rich at all times i can smell alot of fuel on the exhaust.

 

I think this might be a common problem, cause my '94 is doing the same exact thing as as you describe. It does it just for a couple of seconds. To me it feels like when you shut your truck off there should still be some fuel pressure in the fuel rail. I'm thinking, overnite the o ring in the fuel pump checkvalve (if there is one) causes the fuel rail to lose pressure, and when you start the truck in the morning, it takes couple of seconds for the pump to build up pressure again, that is why we get that couple of seconds of roughness, probably from fuel starvation. Than again, an injector with a small leak can also do this. Those couple of seconds are annoying, but right now where I live its a little bit cold do do some playing around with a fuel guage. Once it gets warmer I'll do some tests and keep you posted.

 

Then again, if it was a leaky injector on some cylinder and it would flood that cylinder you might notice a black smoke during that time