ok seafoam and replaced egr regulator
 

ok seafoamed my truck ... couldnt stall it and i was pouring it in .. cut it off waited 25 mins cranked it up and yuppppppppppppp smoked like a diesel with bad injectors ,,,, 30 mins later cleared up ... drove it fine... replaced egr vacuum regulator unhooked battery cleared codes and run koer got 2 codes 41 77 and i turned steering wheel waited and opened throttle wide open ,,,lol my thing is i still notice the stumble in accellaration.. i might get that tps anyway to rule it out ...fuel tank is half full and seafoamed it also and crankcase too ...was going to do the timing bump but ill wait til i get oil changed and tps .. the stumble in throttle makes me wonder... but before i buy anything im driving it to see if it clears up too

No bump till the error codes are gone. Sounds like 77 is still op. error (right thing, wring time). How old's the O2 sensor? Is it connected?

i just got the truck so im following behind someone else

41 means the o2's pooched or possibly disconnected.

i will see about o2 sensors tomorrow its twin lines same converter but duel in and out under passenger side floor board

ok did a quick check o2 is connected and looks old , after doing some reading i have a lean condition maybe a vacuum leak , remeber i said i heard a leak upon shutting engine off , and i found it today i feel sorta dumb it was pvc wasnt hooked in valve cover lololol.. going to retest

I want to seafoam my truck, but its a 91 4.9 with 241,000 miles and im scared its gonna loosen up some grit in the engine and start an oil leak. I am already leaking oil a little bit, and dont wana make it worse. Should i do it? Is it 1 can in brake booster vacuum and 1/2 in oil and 1/2 in gas?

If you want decent MPG, replace the o2!!!

Oil leaks, are oil leaks! Fix em. You'd rather leave sludge & carbon build up in the engine?? :eek: 1/3,1/3,1/3 can. You'd be suprised at how many pan & cover leaks require just snugging the bolts to spec.! https://www.f150forum.com/f33/how-se...-1991-a-31505/

The only problem is we cant find the oil leakes, its not too bad about 1 qt every 2.5 weeks, but we replaced valve cover and upper gaskets. I think i am gonna find somebody with a torque wrench and tighten up all bolts on pan and stuff to spec. I just got outta school for summer so i will prolly do seafoam this week and see what goes down...My truck already runs decent with 241,000 miles so i cant imagine it being a huge miracle, but maybe?