hi first time posting here. i have a 1994 5.2 318 with the 46rh tranny. i purchased this truck in feb with 133k miles and she just hit 150k today. Shes been a great truck but its has been having a weird prob lately. It started as a surge around 40-50 mph happening every now and then. but for the past week it hasnt been doing it as much its now starting to shudder at 40-50 and 60-75ish but not all the time if i tap the brake to unlock the TC she will smooth out or if i push the accelerator to the floor it will smooth out aswell. I have replaced the Tps, fuel pump, taken the Throttle body off and thoroughly cleaned the iac and Tb. Tomorrow will be changing the trans filter and topping it off with New fluid and hoping it doesnt make it worse, cause im sure its never been changed. any suggestions or advice is appreciated


Oh yea one last thing i noticed today it didnt wanna shift into overdrive on the interstate, dropped down to 55 and floored it and it finally went into overdrive

 

i forgot to mention its a 2wd and downshifts hard sometimes(backfires when doing so aswell)

 

Tons of possibilities. Sounds like the distributer may be missadjusted or something.

 

is that a DIY or a shop required? i am fairly decent working on vehicles just not diagnosing them.

 

update. flashed my pcm and changed my trans filter and topped it off with new fluid. the fluid was black with a decent little bit of shavings but drove her 390 miles today and shifted great was hauling about 900 pionds with no problem and it hasnt surged since the flash. still have a vibration that increases around 60-70 though.

 

How did you flash your PCM?

 

My 94 has a vibration that starts at 59.5 and leaves at 66 MPH. Changing out rear brakes I found a leaking wheel bearing on pass.rear side. I think Ill a couple wrecking yards and see if I can find another axil, add a new bearing and do a fast swap since Mrs. Newbies has a dead inspection, I don't want to tie it up only 4 wheeler running. . I HATE DOWN TIME!!

 

well i guess flash isn't the right term but i unhooked my ground from my battery for about 30 mins then reconnected it drove it 130 miles the next day ran fine still vibrated(replacing shocks this weekend) hopefully thats all it is. then did a trans filter change Tuesday and put 5quarts of new fluid in it. almost 550 miles since Tuesday and still shifting great

 

Oh okay. Ya that is not flashing that is just a simple reboot, clear memory ect.