At idle my 1998 seville sts is dropping rpm in surges. Under acceleration it seems to hesitate. I have put premium fuel in it with an octane booster and this did not solve the problem. The car has 60k on the clock with all service through the local cadillac dealer. Help!?

 

forgot to add..... I have an aftermarket air intake on the car. whats wrong guys?

 

what exactly do you mean by air intake?

sounds like your TPS is in need of help, but lets find out what the air intake is all about?




.

 

i bought it off of ebay. Its a k&n air cone air filter attached to a short ram. I removed the factory airbox to install it.

 

this thing:

http://cgi.ebay.com/ebaymotors/98-04...Q5fAccessories

 

A K&N filter will help the engine breath better .. that is not the problem.
so we are back tot he TPS. have it checked. once that is working well, you can start looking at acceleration hesitation if its really there.

BTW, what codes are you showing?

 

These are the codes i pulled:

AMP B1327, U1255, U1064, U1128
DDM B2207
IPC B1652, B1983, U1301
PCM P0300, P1617
RSS C1743, C1783, C1785

i then cleared all codes and drove it around the block. Right before letting of the gas to begin pulling in the drive it sounded like a piece of gravel hit the firewall. After getting back into the garage i pulled this code:

RSS C1743

 

B1327 - Vehicle system voltage below 9.0 volts
B1652 - Loss of Keep Alive Memory (KAM)
B1983 - Device Power Circuit Low
B2207 - Right Rear Window Switch Stuck in Down Position

C1743 - Speed Signal Fault
C1783 - ICCS2 DL Left Output Short Circuit to GND
C1785 - ICCS2 DL Right Output Short Circuit to GND

P0300 - Engine Misfire Detected
P1617 - Engine Oil Level Switch Circuit

U1064 - Loss of Communications with DIM
U1128 - Loss of Communications with IRC
U1255 - Class 2 Communication Malfunction (Serial Data Line Malfunction)
U1301 - Class 2 Short to Battery

If you already cleared the codes it take 3 driving cycles to set a code. so after a few times of driving check your codes again to see if more pop up. Then see if they match the ones you listed and let us know if it only does it at start up and goes away or if the problem is always there.

 

Any repairs done prior to condition? Check condition of grounds at engine and battery cable connections. Small vacuum leak, high resistance in plug wire or coil are also possible causes.