Engine Stumble at 55-60 - Toyota Nation Forum : Toyota Car and Truck Forums

mcgiiver · 03-09-2011, 06:14 PM

'95 corolla, 1.6 engine, auto. Car has only 29000 miles, at about 55-60 mph I feel a pulsation or slight stumble, continuously, Goes away if I go faster or slower. I am not sure if its a wheel balance issue, will rotate tires and see, or an engine issue. If its the engine, does anyone have ideas, spark plugs are new. Air filter is fine. Have run fuel injector cleaner through on occasion since car was new, so I doubt its injectors. Looking for idea that I might not have thought of.

d12boy420 · 03-09-2011, 10:18 PM

I am having the same problem. I recently cleaned the EGR valve took apart the whole assembly including the bottom part which goes to the throttle body. Upon taking it off i noticed that the pipe that goes to the throttle body was clogged and I cleaned it out and then the CEL went away. I would say check the IAC valve it is located on the bottom of the throttle body right next to the intake. Here is another thread with a diagram Rough Idle I am going to try this soon to see if my problem will go away.

mvftw · 03-10-2011, 02:41 PM

Same problem here and it would seem to be the throttle position sensor...possaible bad contact in one spot...I'm living with it...not a big problem to me...

d12boy420 · 03-10-2011, 03:57 PM

Yea I think I might have to replace the sensor too. Hopefully it just needs cleaned. Im going to take off the whole throtle body soon. Will let u know how it goes.

d12boy420 · 03-11-2011, 07:19 PM

Could not get to take throttle body completely off. For the most part though it doesnt look like there is any buildup. I suspect that maybe the IAC valve is bad. Will take a shot at it again when I have some else to assist me. Getting those clips off for the hoses at that are for a coolant are a pain in the freaking ass!!!

mcgiiver · 03-12-2011, 08:31 AM

Rotated tires, no change in pulsation, Also cleaned throttle body, wasn't too bad, but I was surprised with only 29,000 miles on car, the back side of the throttle plate was covered with carbon. Cleaning didn't help, pulsation still there. Still looking for some ideas on cause.

d12boy420 · 03-12-2011, 10:46 PM

Cleaned EGR valve out problem seemed to have went away. Will let you know if I still have a problem