Dear SF: i have a 2002 pont. grand prix. over the last few
weeks i have had trouble with the can being jerky while accelerating
also i tends to do this more the warmer the car gets ie: runs good in th
am but by lunch time it's acting up.
also i noticed this morrning that the tranny didnt seem to be shifting
from 3rd to drive please help any advice will help. thank you.
SF:
Could you give me a little more info please. Do you have any engine light or codes stored that
you know of? What is the engine size and mileage of the car. Also, at what speeds are you
having the jerky feeling. Thanks. Will try to give some help after your reply, SF
Reply,
i have no codes to give sorry. the jerky feelings happen at all ranges but mostly take off
from 0-50 i have even felt it with the cruz set at 70mph. the check engin light comes on and then
goes off from time to time i had it hooked up once and they told me in showed no code so i just
thought it it was the gas cap. the engine is a 3.8 series 2 also the milage is around 120,000.
also when the car jerks i would descrie it as wanting to just die the tac will drop some then pick
right back up when it does this it dose not rev higher though leading me to belive that the tranny
is not slipping but like i said eariler it dosent seem to be shifting into drive from third. at 60 mph
the rpm's are at 3000 when they were normally at 2000-2300.
i hope this helps and thank you very much for your time.
SF:
OK, thanks. Well, any time the check engine light comes on, there should be a code as current,
or in history, even a loose gas cap. That is really the key to diagnosis. Just by you descriptions,
sounds like you may have 2 or more things going on. A common problem for the jerky condition
is a missfire in 1 or more cylinders. Will need to have the ignition system check- plugs, wires, and
also the fule injectors. Plug wires and coils are a common area of problems on the 3800. May
want to view the 'hints,tip,diag.' page to see a pic of 'ignition coil inspection' to see what a bad
coil usaully looks like. Another concern could be a plugged catalytic convertor. They cause a
poor accel. condition (see question #48 from the Q & A list for a grand prix with a similar
condition). Some engine drivability conditions can cause odd shifting depending on the engine
problem. All goes back to the check engine light codes. coil inspecting, pulling trans. dipstick and
check for a nice red color and not a dark burnt color/smell are some things you can do yourself.
After that, getting the codes that are probably still in memory is the next step.
Reply,
ok so i took it to the dealer and they told me that the cadalytic converter is pluged and the map
sensor is bad which is the reason it is not shifting right. then they told me that the recall on the
converter ran out at 120,000 and i have 124,000. so my next question is will the can run
properly with out the converter or are there sensors built in to it? also how do i change the map
sensor? the car is a 2002 pont. grand prix.
SF:
1- It is against federal emmision standards to run a car without convertor.
2- With a convertor removed you will definatly have a check engine light and codes. The oqygen
sensor behind the convertor monitors convertor effeciency. You will get oqygen sensor codes,
and possibly drivability concerns because the computer will be trying to adjust air/fuel ratio after
seeing incorrect readings from post convertor oqygen sensor.
I will attach a pic of MAP sensor location and send shortly......Back
weeks i have had trouble with the can being jerky while accelerating
also i tends to do this more the warmer the car gets ie: runs good in th
am but by lunch time it's acting up.
also i noticed this morrning that the tranny didnt seem to be shifting
from 3rd to drive please help any advice will help. thank you.
SF:
Could you give me a little more info please. Do you have any engine light or codes stored that
you know of? What is the engine size and mileage of the car. Also, at what speeds are you
having the jerky feeling. Thanks. Will try to give some help after your reply, SF
Reply,
i have no codes to give sorry. the jerky feelings happen at all ranges but mostly take off
from 0-50 i have even felt it with the cruz set at 70mph. the check engin light comes on and then
goes off from time to time i had it hooked up once and they told me in showed no code so i just
thought it it was the gas cap. the engine is a 3.8 series 2 also the milage is around 120,000.
also when the car jerks i would descrie it as wanting to just die the tac will drop some then pick
right back up when it does this it dose not rev higher though leading me to belive that the tranny
is not slipping but like i said eariler it dosent seem to be shifting into drive from third. at 60 mph
the rpm's are at 3000 when they were normally at 2000-2300.
i hope this helps and thank you very much for your time.
SF:
OK, thanks. Well, any time the check engine light comes on, there should be a code as current,
or in history, even a loose gas cap. That is really the key to diagnosis. Just by you descriptions,
sounds like you may have 2 or more things going on. A common problem for the jerky condition
is a missfire in 1 or more cylinders. Will need to have the ignition system check- plugs, wires, and
also the fule injectors. Plug wires and coils are a common area of problems on the 3800. May
want to view the 'hints,tip,diag.' page to see a pic of 'ignition coil inspection' to see what a bad
coil usaully looks like. Another concern could be a plugged catalytic convertor. They cause a
poor accel. condition (see question #48 from the Q & A list for a grand prix with a similar
condition). Some engine drivability conditions can cause odd shifting depending on the engine
problem. All goes back to the check engine light codes. coil inspecting, pulling trans. dipstick and
check for a nice red color and not a dark burnt color/smell are some things you can do yourself.
After that, getting the codes that are probably still in memory is the next step.
Reply,
ok so i took it to the dealer and they told me that the cadalytic converter is pluged and the map
sensor is bad which is the reason it is not shifting right. then they told me that the recall on the
converter ran out at 120,000 and i have 124,000. so my next question is will the can run
properly with out the converter or are there sensors built in to it? also how do i change the map
sensor? the car is a 2002 pont. grand prix.
SF:
1- It is against federal emmision standards to run a car without convertor.
2- With a convertor removed you will definatly have a check engine light and codes. The oqygen
sensor behind the convertor monitors convertor effeciency. You will get oqygen sensor codes,
and possibly drivability concerns because the computer will be trying to adjust air/fuel ratio after
seeing incorrect readings from post convertor oqygen sensor.
I will attach a pic of MAP sensor location and send shortly......Back
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