We have a 1999 Isuzu Rodeo 4 cylinder 2.2 SUV with about 96K miles on it. The car has always ran fine but recently it began to idle rough. The check engine light has been coming and and going off for several months now, Other than the rough idle, it runs fine. We have changed the spark plugs and spark plug wires within the last few weeks but it still idles rough. Any ideas would be appreciated.
Doug and Patty
At the least you need to see what code(s) are stored in the ECM. They may lead directly to a faulty component or just direct you generally towards areas to test. The best case would be if you had an individual cylinder misfire code (P0301 to P0304); then you could isolate that cylinder and test spark, compression and fuel delivery. Many causes of a rough idle symptom will either send unburned gas into the catalytic converter and lead to it's early demise or result in lean operating conditions that are damaging to your engine. In all cases, a rough idle results in degraded fuel economy.
Your problem could be as cheap as a leaking PVC hose and as expensive as a cracked cylinder head.
Toyota MDT in MO
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.