Engine Troubles with my '07 4.0L

Hey all, new around here. I've had my runner for about a year now and have had my share of problems with it. Apparently the cylinders were bad so I ended up having the engine replaced. However shortly after having it replaced I started having the same/similar issue.

Problems:
- Christmas Tree Dash Lights
- Feels under powered
- When putting my foot down to accelerate in higher gears is shift funny and bogs down/rumbles, I have to release the accelerator and push down again to get it to change into a lower gear for more acceleration, and even then it doesn't feel strong.
- I smell gas pretty heavily
- This occurred about a month after getting the engine replaced, in that time it drove fine.

Any help or thoughts would be appreciated, I have pulled the codes from it a few times and it either says cylinder misfire which is what I was getting before the swap, or a cat problem.

Thanks!

 

Gas cap loose? Leak in the fuel lines? Failed fuel filter? Fuel pump? Transmission electrical input/servo issue? Any codes thrown when reading the OBD II port? What did the mechanic say when you were fixing to replace the first engine?

 

I would take it right back to those who replaced your engine and let them figure it out on their dime. Should be under warranty if you got one.

 

What he said. If what you've told us is true, common sense would dictate that you take it right back to the shop that did the work.

Anything else is simply chasing your tail.

 

Check and clean the mass air flow sensor.

 

Hey all sorry for the late reply but thank you for all those who replied.

Unfortunately the troubles started right after the warranty expired for the engine (go figure).

I have since replaced my gas cap to see if that was the cause and its still quite loose, thinking I might have to replace the fuel fill neck.

As for the codes I pulled I'll have to run it again to get the specifics and I'll report back on that. Today I'm going to try chasing the fuel lines to see if there are any kinks or pinches, thinking the engine might be running to lean or starved of fuel, and also going to clean the MAF. Thanks all!

 

When replacing the engine the first time the mechanic I took it too said that a couple of my cylinders/valves were messed somehow and it would be cheaper to get a new engine than pay for all he labor of a valve and cylinder job.

But I was picking misfire codes on the old engine from multiple/random cylinders.

 

Eldrez... how many miles on your 4runner when the problems started? And what problems did you have? Can you be more specific?

I have a 2005 with 170,000 miles and have owned it since new, and it's been trouble-free. OEM tranny and engine.

My 4runner has never tripped a code! Doesn't use oil or burn any. I'm hoping for another 150,000 trouble-free miles from here.

 

That's pretty specific...

 

Just FYI, a bad gas cap can and will cause the check engine light to come on, but it won't affect the running.

 

When replacing the gas cap i use oem cap. Never had any luck with aftermarket ones

 

Last year driving into Wyoming that same thing happened. We attributed it to bad gas. We finished our trip driving to Idaho and had been fine since- until right now. Driving into Wyoming again and same thing except this time we have a camper!
Both times it was hot, 90+ and around 4-5k feet elevation. We actually turned around and started driving back to Nebraska this time. Seemed like it got better so we turned around and made it to Laramie. We’ve been driving around all week in the mountains and it hasn’t done it again. Still feels under powered though. Brought my scanner this time. Did get a too lean dtc while it was doing its no power thing.
I was thinking clogged cats or bad/clogged fuel pump. I replaced the fuel pump a couple years ago, ran it with it not working completely and suspect I damaged the cats then? I’ve searched a lot for this since last year and you’re the first person that seems to have had the same experience or at least worded it the same- haha. Please post your conclusion and will for you as well. Hopefully we make it back to Nebraska without issue this time, its downhill so hopefully. Haha
Best of luck!