Hi,

My Turbo Intercooler has recently gotten 17 mpg which is really bad compared to the already bad 20mpg. I usually use 92 octane chevron gas, or 94 octane. Up hills mostly, if I really put the pedal down, I feel a bit of surging, or like the engine is faultering. When it's cold and I step on the gas, most noticeably after a corner, the car drones and takes a while to accelerate. It's got a new Air Mass Meter, new CIS/IAC motor, new turbo downpipe, new radiator, new thermostat, new fuel regulator. What more could need replacing!? I unplugged the O2 sensor sender and it seems to idle a bit more smoothly, but otherwise no big improvements.

Any other ideas?

Thanks

I've got the same problem(s). I've got lots of new stuff on the engine (too much to list but it does include the hall sensor, temp.sen. and fuel pressure reg.) The only FI componants I haven't changed are the ECU and the O2 sensor. The O2 sensor checks good. I got some relief from an oil treatment of Marvins Miracle oil and subsequent oil change. I got 1 additional MPG on the first tank and I'm on the 2nd tank now. Seems to be better than the 1st. One strange thing is that people either report MPG of 17 or 20-21, nothing in between (mines been running 17 for awhile). This almost seems too common not to have a common cause.

Hey all,

Again.....

My volvo 740 NA 1988 model has the EXACT (i mean exact - but fuel economy isn't all that bad, i drive it very easy) same problems as JSK..........i get the surging, but what i noticed the most is what i could almost describe as "flooding" (when you come around a corner in second, about 30 seconds after you start the car, and push the pedal just after the turn the car feels like it has either got toooooo much fuel or wayyyy not enough......i can't work it out...........i also get (still....) what seems to be missing cylinders when you are in 4th doing 60k's an hour, and you hold the pedal right on the point where it keeps the car at the same speed.......my O2 sensor wires are bright white, so i assume, it would be new, but everything else (AMM, IAC, etc) are 200000k's old! New spark plugs, cap and rotor......what the hell could it be? Could it be one of the computers? (i have a new thermostat, but the old sensor is still there) Could it be (more likely) a sign that the hall sensor is going bad? Oh, my ovlov is also a manual.......5 speed, not overdrive!

Please HELP!

Sounds like a major mixture problem, possibly running rich. Take a look at your engine coolant temperature sensor: if this goes south, the mixture enrichens quite a bit and results in poor idle, poor performance and poor mileage.

Cheveron gas may be oxygenated in some parts of the country during the winter. like in the northern states. Try a tank of Texaco prem.

Might help a little. Robert 1990 744, 55k

I read someplace that Chevron pulled some strings recently & got a governmental greenlight to put out some substandard gas for a limited time. The last three times I bought Chevron when I shut off the key the engine kept running -- run-on. I filled up on Texaco the other day & got octane knock on level ground. I give up!