: 99 Deville Hesitation during Acceleration



KJE36610
05-11-08, 01:38 PM
This past week I have notice a hesitation (almost like its not getting enough gas, that type of hesitation) during acceleration around 40 mph up to 70. Then after a certain point of driving, the hesitation go away. The car has not set a check engine code or anything. If anyone have had problems like this your help would be greatly appreciated... :hmm:

Ranger
05-11-08, 02:53 PM
Check the fuel pressure during acceleration.

KJE36610
05-17-08, 01:36 PM
How do I test the fuel pressure during acceleration??
Could it be the spark plug wires (new spark plugs) since the car has 106,000 miles?

Submariner409
05-17-08, 02:18 PM
Take the engine cover off this afternoon and leave it off tonight.......after DARK, start the car and take a long, hard look around the coil pack and the wiring. Any arcs and sparks ?? New ACDelco wires. www.rockauto.com (http://www.rockauto.com).

Make very sure the correct plug wires are placed on the correct towers as your car uses a waste spark system in which each coil fires two plugs simultaneously. It is easy to get that setup 90 degrees out of whack. That causes anything from lowered performance to outright backfire, depending on which cylinders are incorrectly wired.

Fuel pressure is checked with a remote gauge tapped into the fuel rail Schrader bleed fitting outside the car cabin.

RickyHenry
05-17-08, 02:35 PM
I know this might sound simple, but, any chance the throttle cable is getting partially stuck at the position where you open it up and notice the rpm difference?

Ranger
05-17-08, 04:11 PM
How do I test the fuel pressure during acceleration??
Could it be the spark plug wires (new spark plugs) since the car has 106,000 miles?
You need a fuel pressure gauge attached as Sub said. Preferably one with a long hose on it so that you can tape it to the windshield and watch the pressure change during acceleration.

To add to what Sub said about inspecting the wires after dark, get a spray bottle filled with water and mist the wires. If they are bad, you'll know it.

KJE36610
05-25-08, 06:42 PM
Last night I got a spray bottle w/water and sprayed a mist on the spark plug wires, I did not see anything. This morning the car finally said service engine soon (to add it was running very bad). The codes are PCM P0300, P0440, P0603, P1527, and P1566. I know one of the codes is a misfire, so I went ahead and replaced the spark plug wires, and I must say that it is now running smooth again :bouncy:. The only problem is, what are these other codes :hmm:??

Ranger
05-26-08, 04:45 PM
Look them up.
http://myweb.accessus.net/~090/dtcobd2.html