extreme carbon build-up

Hey guys,

I have a '97, 2.7L, 4x4, with 192,000 miles on it. It recently started sputtering, so....
I started with the plugs and wires....still sputtered
then, I cleaned the mass air flow sensor....still sputtered
then, I replaced the fuel filter...still sputtered
then, I replaced the Oxygen sensors....still sputtered
then, I replaced the fuel injectors....still sputtered, but I noticed something:
after removing the throttle body, I noticed extreme carbon build up that coated the throttle body, intake manifold, etc. I believe this was choking the engine. I need to seafoam the engine, clean the egr valve, and change the pvc valve.

Anybody else have any other ideas? I'm about out of stuff to replace...

 

I would run the seafoam first and see how much better it runs.

 

It is not throwing any codes?

So did you actually clean the throttle body (I am guessing yes) and did it help at all? Although it doesn't seem to appear on any official Toyota maint. intervals that I have seen, TB cleaning is a recommended as-needed item.

Seems like the EGR would be the next most likely culprit.

Have you closely inspected all vaccuum lines for cracks/brittleness/fit?

 

I'm not getting any codes and haven't gotten any codes to date. I cleaned the throttle body and it did help a bit.

When I replaced the fuel injectors, I did an inspection of my vacuum lines. They are still all soft and pliable. I don't think there are leaks in the vacuum system.

today I will seafoam, then maybe this weekend I'll pull the egr valve and clean that. I don't have the money right now to replace the egr valve, so hopefully a cleaning will do the trick.

 

Ok, so I disconnected my brake booster vacuum line and let the engine suck up seafoam. I did this four times! Each time it billowed white smoak like noone's business! I also replaced the PCV valve. I also learned that there is a filter on the EGR valve that needs to be cleaned. I cleaned this, too. Trucks runs way better, but I think I will have to keep doing a seafoam treatment every once in a while until I feel the engine is clean. I'm also going to manually clean the EGR valve one of these days, but that'll have to wait for a weekend. I think I'm about there as far as fixing the problem...let's keep our fingers crossed. Thanks for the help and if there are any other thoughts, then let me know.