• A few problems can cause the 1988 Pontiac Fiero to idle highNew car petrol engines image by Christopher Dodge from Fotolia.com
  
  High idle in a 1988 Pontiac Fiero GT 2.8L engine occurs when the vehicle is stopped and the engine is running. The symptoms of idle problems in the Fiero are engine backfire, stalling at stops and the engine misses out during operation. Only a few things causes the 2.8L engine to idle high.
  
  

AIS Motor Problems

• The automatic idle speed motor (AIS) controls the air flow in the 1988 Pontiac Fiero GT 2.8L engine when the automobile is at a stop. The AIS motor allows a small amount of air into the injector system so the engine idles properly when the accelerator is not being pressed. Corrosion and debris does build up in the AIS motor over time and the device has a tendency of seizing causing the Fiero to idle high. The motor can be removed, cleaned and lubricated unless too much corrosion has built up in the device.
  
  

Vacumm Leak

• A vacuum leak is the most prominent cause of a 1988 Pontiac Fiero GT 2.8L engine to idle high. The hoses and air lines in the Fiero engine must be tight and without any damage; this damage may allow the air flow to leak out instead of into the 2.8L engine. The air lines which lead to the manifold and throttle of the Fiero engine are the most common lines which create a vacuum leak. The lines can be removed and inspected for damage, tears or leaks by visual inspection, but the best way to investigate a vacuum leak is to take the Pontiac into the dealership and have the vacuum leak narrowed down by a professional.
  
  

Intake Manifold Gasket

• A damaged intake manifold gasket can cause the 1988 Pontiac Fiero GT 2.8L engine to idle high. Even though this problem is rare, a leaking intake manifold gasket allows air to be released into the engine compartment and prevents a continuous flow of air into the manifold. This high idle cause is difficult to repair for a novice and the gasket should not be replaced by someone who does not have the proper knowledge of the Pontiac Fiero GT 2.8L engine. Once the intake manifold gasket is damaged, the Fiero will begin to stall, cough or hesitate during acceleration.