Has high idle, replaced iac valve, temp sensor, tps, complete tune up, checked vacuum leaks (unable to detect any leaks) and its still idling high and check engine light is on, new fuel filter. PLEASE HELP. Don't know what else it could be. ANY SUGGESTIONS?????
check the iac valve for power if not the ecm is bad or the wiring to the iac valve could be broken in the harness.this is got to be an iac valve issue.
remove neg. cable from battery so the ECM will reset this may work. make sure the IAC is air tight. if this doen't fix your problem have someone check the IAC valve if it's bad the part runs $300.00 pluse
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It seems like the problem lies with the engine management system, rather than the brakes. Given that you've already replaced the MAF, MAP, and TPS sensors, here are some other things to check:
1. Vacuum leaks: Inspect all vacuum lines for cracks or damage that may be causing a leak. A vacuum leak can cause erratic idling, poor acceleration, and stalling.
2. Idle air control (IAC) valve: The IAC valve controls the engine's idle speed. A malfunctioning IAC valve can cause the engine to stall during idling. Try cleaning the IAC valve with carburetor cleaner and see if the issue is resolved.
A few things to check would be the coolant temp sender, TPS sensor and last but not least check for a vacuum leak. These are just a couple things off the top of my head.
If you have the 5.0 liter engine or the 5.8 litre there was a problem with the upper intake manifold gasket being cracked and sucked into the intake causing a vacuum leak and the result was high idle. Also a leaking egr will sometimes cause high idle.
It's very common for these engines to develop a vacuum leak around the base of the throttle body. You can check for this with a stethoscope or a can of aerosol carb cleaner. Also, IAC valves are a common problem, but easy to clean before you replace it. Remove it and use the carb cleaner and a brush to remove the build up, also the crud inside the IAC orifice. Next clean the throttle butterfly valve and throttle bore thoroughly with carb cleaner. If this doesn't help, remove the egr valve and try and poor a little paint thinner through it when you're holding it upside down, it may weep a little through the pintle but it should not obviously allow the paint thinner to flow through. If all of this fails to help, you'll have to get your hands on a scan tool and read IAC counts at idle to see what the computer is trying to do. If the counts are high...above 50, the computer is trying harder to open the IAC to keep the engine running because of some kind of problem, usually mechanical. If the counts are very low...below 5, the the computer may be trying to counter a vacuum leak that is providing most of the idle air, which is unstable and can cause the stall.
Can you check fuel trims at idle and under load?
If fuel trim is high at low speed and load, look for a vacuum leak.
If fuel trim is high at high speed and loads, look for fuel volumn problem or restriction.
If fuel trim is high at all speeds and loads look for pcm input fault, maybe a maf sensor problem?
If fuel trim is negative low speed and load, look for fuel pressure regulator or injector leak. If fuel trim is negative at all speeds and loads check ect and iac.
If you have the spider fuel system, that system is noted for problems. key on engine off, 60--66 psi fuel pressure.
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