1996 Pontiac Bonneville Shifting

Hi opuspr,

Thank you for the donation.

Problem seems to be due to a loss in engine performance.

Is the Check Engine Light indicating?
Have you tried to retrieve for trouble codes?
Was any repairs carried out prior to this occurring?

Here is a list of probable causes.

LACK OF POWER, SLUGGISH OR SPONGY
Symptom Definition
Engine delivers less power than expected. Little or no increase in speed when accelerator is pushed down.

Possible Cause & Correction
Check following items:

"Â Ensure air filter and fuel filter are not plugged. Replace if necessary. Check for incorrect
fuel pressure. Also check for contaminated fuel.

"Â Check shift solenoid system and TCC system for proper operation.

"Â Check knock sensor system for excessive retard.

"Â Check ignition control system for proper operation.

"Â Ensure EGR valve is not open all the time.

"Â Check exhaust system for restrictions, such as a damaged or collapsed pipe, muffler or catalytic converter.

"Â Check charging system output. Repair charging system if voltage is less than 9 volts or more than 17 volts.

"Â Check for A/C clutch cutout at wide open throttle.

"Â Check MAP sensor.

"Â Using Spark Tester (ST-125), check for available secondary voltage.

"Â Check air induction system for restrictions.

"Â Check engine valve timing and compression.

"Â Ensure the installed PROM is correct for that particular vehicle. Check with dealer for latest application information.

"Â Check PCM grounds for clean, tight connections.

"Â Check for incorrect or worn camshaft.

"Â Check for excessive fuel additives.

"Â Check for binding accelerator cable.

"Â Check distributor vent system (if equipped).

"Â Check engine supercharger (if equipped).

"Â Check if engine is operating in power management mode (if equipped).

"Â Check boost control system components and connections (if equipped).

From symptom descriptoon, I would suggest starting with the EGR system.