Slow acceleration

I've got a 2007 base model with the 2TRFE 4 cylinder, automatic, 115k miles, and it is incredibly slow. I clocked 23 seconds from 0-60 mph. No codes and fuel trim is dead on, never wavering more than 3% either way on both the ST and LT. Brand new air filter, brand new plugs. Just did the coil packs because I was getting a bunch of misfires but now it's better. Took the cat off and checked for clog, it looks brand new. Getting a solid 40psi on the fuel pressure with good flow.

I'm stumped. I just changed the injectors thinking that might be the problem considering I ran shitty gas for 10 years before I knew any better. Runs exactly the same.

Oh I was getting knocking at like 20% acceleration, I figured it was running lean and choking itself which also pointed me towards injectors. I haven't driven it enough on the new injectors to tell if the knocking went away (it mostly did it when I went down the mountain, up in the mountains I don't have that problem as much).

I'm thinking throttle body? Maybe the plate motor isn't as responsive... although when it kicks down gears there's no hesitation. It just has no balls.

Perhaps O2 sensors? It's reading perfect lambda though. Plus, like I said, no codes.

Any ideas before I throw more parts at this thing?

 

Carbon on valves is my wild ass guess. If they aren't shutting fully it doesn't always cause a misfire code.

23 seconds is mega bad.

snip!

Have you done a compression check yet?

Have you tried to drive without the cat? Or just remove the AF sensor?

Edit: unplug the o2 sensors and drive around in open loop to eliminate the idea of o2 sensors.

 

I just did fuel pressure at idle. Rented the tool from autozone and it didn't have the proper adapters so I had to hold it onto the fuel line by hand lol.

Haven't done a compression check, I didn't think there's any way the rings could be bad at only 115k but I didn't think about the valves.

That's a good idea, run it in open loop and it will rule out the O2 sensors. Going to go try that now. Thanks!

 

2.7L of this area had a recall for clogged catalytic converters. No sure if its still active but it sure sounds exactly the reason for the problem you are having.

 

The 4 banger doesn't have a two speed fuel pump...

 

Figures, at least I didnt say "cats"

We don't see many 2.7's. I haven't worked on one in ages.

 

Carbon on the exhaust valves sounds about right. Meets all the symptoms and I smell raw gas from the exhaust when I first start it. Hopefully none of them are burnt. For the majority of the trucks life I commuted only 4 blocks to get to work without letting it warm up first, with the occasional weekend trip to the store. I did an injection service/decarb about a year ago but it might not have been enough. I'm going to pour water down the intake while it's running to steam clean them and let you guys know if it works (in case someone else has this problem later on).

 

A four block commute makes you the poster child for walking, bicycling or an EV.

And yes, clean your throttle body.

 

Yea

go buy a new EV for your 4 block commute

 

I live in California. We don't walk. If I could find a way to drive from my bedroom to the kitchen I would.

 

Thats the best thing Ive read all day

 

I work in CA. I take an airplane to work.

 

You could try a can of jectron with a tank full of premium. Then run it hard, get it good and hot, then find a long hill and floor the hell out of it uphill. Something I try to do at least twice between 6 month oil changes. After idle is smoother, mpg better, acceleration better.

$11 Liqui Moly 2007 Jectron Gasoline Fuel Injection Cleaner - 300 ml , blue , 10.14 Fl Oz (Pack of 1 )

https://www.amazon.com/Liqui-Moly-2...motive&sprefix=jectron+,automotive,171&sr=1-1

 

Finally back at the shop. Leakdown test in cyl 1 had air coming out of cyl 2: blown headgasket. Pulling the head now.

(FYI if you're taking the timing chain cover off there's a secret hidden bolt under the water bypass pipe)