In my 99 Monte carlo 3.1L with 133k on it. been occuring for for the last 2 years maybe... this is in Southeast Missouri
symptom: shudders at times, like a cylinder missfired ( best i can describe it at the moment)
History:
- the past winter(2 years ago i think) service engine light came on - went to auto zone, cylinder 4 misfire code, replaced wires at that time , no proof that did much
- misfire code came on again last year during winter (pretty sure) did nothing
- assumed misfire code 2 times in the past month, early month and late month
- trans never serviced to my knowledge,but fluid is still at "full" level, bought second hand (the car) at 100k miles in "03
more conditional things:
- doesn't do it constantly, seems slightly random at times
- sub 50 degree weather usually makes it worse.
- problem almost allways happens under 1500rpms, sometimes in all the gears.
- this is normally more prevalent when not fully warmed up.
- the car can stay in 4th down to about 33mph ~ 1100rpms? even uder about 1/3 throttle, shudder noticeable definatly up to 55mph at least under heavier throttle(no upshifting)
- temp gauge in cold to fair weather, seldom sees what could be something close to 160 - 180 range, more like 140, maybe. but still warms up quickly, like allways
: related?---or other problem---
- i do have a gas gauge that is almost allways full , only sees a resonable reading when left over night at house, on flat area, and started in the morn till i start to back down a hill (driveway) no, noone's putting gas in the thing
my ideas: any of these crazy?
- crank position sensor, iffy?
- bad injectors? i have used the pour in cleaning stuff, sometimes more than's needed in 1 tank(bottle for 21gallons in a 16ish gallon tank), and tried several brands
- bad coil?
- M.A.S.? mass airflow sensor? new filters seem to do nothing also
-- your part--
recommendations? suggestions?
did you at least like my layout of this post?
anything?