Hesitation and bogging with 92 Z34

[TURBOLUMINA]

Hey guys, my new z i picked up has some drivability issues. When its cold, it runs fine. once it pulls temp, it acts like its lean and bogging under part to half throttle. If you go past half throttle, it takes off like hitting a power band, especially at about 3500 rpm. I know it cant be the tps acting up because it only does it when warm. Anyone think that its the coolant sensor or possibly the map sensor? its had all fresh tuneup and timing belt done about 10k ago. so it definitely seems sensor related.

[BIGBULS]

O2 sensor would be my guess.

 

Those symptoms almost exactly match a shorted O2 sensor's symptoms (and is exactly what mine did).

[pontiacmaniac94]

tried gutting the catalytic converter? might be clogged.

 

also, your EGR valve might be bad, that would cause it to run crappy when it was warm and not when you first start off.

 

check the EGR, it could be stuck open, and would also cause a loss in MPG, because the motor would try and run richer to compensate for the extra exhaust.

 

just an idea.

[GOT2B GM]

timing might be wrong, my Z34 was like that when I first bought it. It also had a "Fresh timing belt" Retimed it and all was good.

[TURBOLUMINA]

when the egr goes bad dont you almost always get a check engine light? the mileage is struggling on it some. Im not getting any check engine so it makes this that much harder. I hate wasting money on buying sensors just for fun. I dont think its O2 sensor because when they go bad the car defaults to full rich mode. Exhaust is good. car only has 60k on it and i get good flow out the tips

 

[pontiacmaniac94]

when the egr goes bad dont you almost always get a check engine light? the mileage is struggling on it some. Im not getting any check engine so it makes this that much harder. I hate wasting money on buying sensors just for fun. I dont think its O2 sensor because when they go bad the car defaults to full rich mode. Exhaust is good. car only has 60k on it and i get good flow out the tips

 

 

 

it wont always throw a code, mine was bad for the a week or two before it actually threw the code, and even then, it would come off and on....you can always just check the EGR before you replace it. see if it is leaking exhaust from the valve itsself.

 

also, if you dont feel like replacing it, you could always delete it, make a plate to cover the hole, put the EGR valve back on, and keep it plugged in. that way the computer thinks it is still working and doing something, and wont throw anymore codes.

 

that will work as long as the car is OBD I or OBD I.5, (if that is what you want to call that half year)