Hello,
I have a beater, 1995 Saturn SL1. 4 cylinder, 5 spd stick shift, single over head cam. Been a great, reliable car, but ...
In the last 2 weeks, the fuel economy went from 32-34 mpg to about 22-23 mpg. There has been no change in my route, driving behavior, etc... just getting BAD fuel economy. And this fuel consumption comes with a symptom of a high idle speed (1700 RPMs) but only when the car is rolling.
That's right.. weird... let me detail this out:
Three weeks ago, if I kicked in the clutch at, say, 30 mph to prepare for a stop, the RPMs would drop to about 700 as I rolled down to a stop. NOW.... if I kick in the clutch, the RPMs hover very steadily at 1700 RPM. The darn thing will NOT drop down until I come to a complete stop, and have held the car at a full stop, for about 2-3 seconds. This just started 2 weeks ago - and that's when the mileage went to pot.
One more thing - if I'm stopped, and lets say I'm on a downward hill, the RPMs are at 900 (as low as it's goes now) and I let my foot off the brake, and just start coasting - without touching the gas or letting the clutch out, as soon as I start rolling, the RPMs jump up to 1700 RPM.
Anyone got any ideas? I'm thinking fuel injection, but perhaps there's a simple speed sensor or something like that? Maybe a sensor in the throttle body or intake is telling the computer to push more fuel???
I'm pretty handy around the cars/engines. Not a mechanic, but definitely shade tree mechanic material so feel free to get a little technical. You can definitely assume I know how an engine works, and plan to fix/replace stuff myself until I find the fix.
Car has 160k miles on it. Original fuel injectors, fuel pump, etc. It's been very reliable, well maintained. This is the first real %26quot;problem%26quot; that isn't maintenance.
Thanks in advance...Was getting 32-33 MPG - now I%26039;m getting 22, and the IDLE speed is VERY high?
Sounds to me that it is more of a problem with your Mass Air Flow sensor, that sensor sends a value based on the air intake which allows your cars ECU to regulate your fuel to air ratios. If it is malfunctioning it could result in your car running rich (dumping more fuel than needed), in turn this would also result in your engine working harder to burn the fuel, hints the high rpms to keep running when idle. Any way its just an avenue to investigate, good luck to yaWas getting 32-33 MPG - now I%26039;m getting 22, and the IDLE speed is VERY high?
It could be as simple as the thermostat: stuck open, the engine will take forever to warm up, and it will be running rich. Any unusual behavior at the temperature gauge?
Another possibility: the %26quot;air mass meter%26quot;. This is a device that measures the amount of air flowing through the intake, and sends a signal to the computer. A wrong indication might also cause a too-rich mixture.
