what can this be?car start and shakes

[antoniobanderas]

my car its acting up again ,in the morning when first started it will stall if i dont keep it on idle for at least 8 minutes and it will die several times still,then it will run just fine,i let it seat later on,come back one hour later,same bs stalling ,replaced the fuel pum ,no change,the plugs,the ign cables ,no change,the filter looks fine ,it will blow thru fine,the maf sensor i replaced olso,no change,why its only when i first star the car?it seems temp related? could it be the ECM? any idea? its getting worse and worse:( i changed the pcv olso,no change, put a new oxigen sensor,,no change! damm!

[Themeneea]

when you first start is the car idleing high?

[antoniobanderas]

not really,it shows like 800 rpms only ,in N 650 in D

[Colin]

CTS , coolant temp sensor . :???:

[92CamaroRS]

EGR?

[antoniobanderas]

NO,it works as suposted when i push diagram it gets reall bad it gets no vac at idle, the temp send a signal as it shows a reading in the instrument cluster

[92CamaroRS]

not sure on the 3.3 but i know my my Camaro that it has one sending unit for the gauge and one for the computer. so even if the one for the gauge is good the one for the computer could be bad.

[doobiess]

Isnt an O2 sensor possible and remember your ecm light dont have to come on for it to be bad..

[92CamaroRS]

not really. not when its acting up. it acts up until it warms up and an O2 sensor doesnt start working until it reaches aprox. 600* F so cold the computer runs a set table of parameters and doesnt factor in anything from the O2 sensor. now if this happened after it warmed up it would most likly be the O2 sensor. ither way it wouldnt hurt to check the voltage that its putting out.

[antoniobanderas]

i forgot to mention this,,in the winter,the car ran ok,its only now that its warm ,in the winter the rpms went to around 11000 now it nevers go to high idle even in the morning

[92CamaroRS]

sounds like the computer is thinking the motor is warm all the time.

[rixGAphx]

Classic symptoms of a clogged catalytic converter.
As the exhaust warms, the cat becomes more efficient and opens a little space for freer-exhaustng.

BUT, you may also have a bad o2 sensor or other component that caused the engine to run rich and load-up the cat.
What did the plugs look like? Normal, or crudded, or burned?

Go to a quality muffler shop and have them check for clogged cat.
Most will do this simple test as a free courtesy.


Good luck.
-Rick

[antoniobanderas]

i just recently had the entite exaust replaced ,pipes from front to back,car passed emisions test ok,its just the nagging stalling for two blocks or more ,then it setlles and runs fine,untill the i stop the engine,let it seat for a hour and restat,the story repeat over:???:

[92CamaroRS]

doesnt matter if its new if you have a failing O2 sensor. it might be causing a rich condition therfore overworking your cat and causing it to prematuraly fail.

[HeyDace]

Sounds more like a sticking/inoperative IAC and possibley a coked throttle bore also.