: pulsating engine and trans kickdown too high

03-22-11, 05:01 PM
Hey guys, I've been learning from everyones accumlative knowledge for about four months.I have always worked on my own autos ,and I still do.Sometimes we need advice and for that I say thank you.To first problem,the engine around 2800 starts pulsating ever so lightly, a gm mechanic while doing other work to it said the injecters were clean. If I push it around 4500 or so a 0151 comes on 02 sensor bank 2 sensor1. would the sensor cause that pulsating engine problem? Item #2,lets say35 or 40 miles an hour the tranny kickdown will only activate if the peddle is pushed all the way down, here is where I dont know if the kickdown is manual or electronic and dont want to mess with it until I find out. I can see where one problem could be related to the other.thanks guys (or ladies) Ed

03-22-11, 06:43 PM
P0151 - low voltage, B2S1. Check the wiring harness and pigtail connector to the front (left) exhaust manifold O2 sensor. Not fun.

Absent any other P codes, transmission kickdown is electronic/load controlled. 35 - 40, steep hill; it should kick down when engine rpm falls below the values posted in the shift tables in the GM Helm Factory Service Manual. eBay or www.helminc.com. Flat road, easy cruise.......mine will drop TCC and kick to 3 with about 3/4 pedal. Instant shift with WOT (passing) situation.

From a slow start, moderate acceleration, flat road; do you feel 3 distinct shifts up to 43 mph, then a further rpm drop as TCC engages ? Depending on your drivetrain (car model) there is a current thread concerning speed vs. rpm graphs close to this one. Read the whole thread and see if you come up with some ideas.

Hey !!!!!!!! Welcome Aboard ------------:highfive:

03-24-11, 02:40 PM
thanks submariner409,for the high five also..ok satisfied with kickdown, checked it out on the way home, which brings me to the pulsate problem,i used a hand scanner couple of minutes ago ran down through the info and it said there was not a misfire issue also if it helps the timing advance idling fluxated between11.5 and17.5 at 623-646rpm at 1900 it went to29.5. i could be incorect in thinking it is not a misfire, maybe fuel or timing plus the sensor,i have not checked for low voltage on the sensor because if its bad i want to change it then.bosch has a 1 year warranty denso has a three month one i wanted to check rippypartsfor a gm part. but i havent posted enough threads yet to get chris directly, ..perhaps he will read this and reply. as for the rest of us good luck with your projects..and feel free to voice your comments (fyi, its a'99 eldorado vin1G6EL12Y8XU608246).....later ed