Not necasarilly. One thing I thought of is to check the Idle Air Contorl Valve. It is located omn the intake manifold near the throttle body. It will have an electrical connector or a large vacuum line going to it and may have coolant lines going in and out of it. They change the A/F ratio by changing a port that by passes the butterfly and comes out in front of it in the throttle body entrance. To test a vacuum signalled IAC, remove the IAC and run the motor. Reomve the vacuum and see if the plunger or diaprhagm moves freely. In an electrically signalled IAC, test it by removing it and while running removing the connector and seeing if it moves. Sometimes the port or the pluger gets carbon deposits that require it to be cleaned. Always clean out ports psraying from the outside in towards the intake so you don't puch deposits furhter into ports. Don't use carb cleaner on rubber parts, use brake cleaner.
Checking the fuel pressure will tell you 2 things. If the pressure with the vacuum line on is at spec, the fuel pump is okay. If the pressure does not raise to spec when the vacuum is removed, the fuel pressure regulator may be bad and need replacement.
Wednesday, November 23rd, 2011 AT 3:03 AM