This is on an 85 Golf. I think my O2 sensor is bad, I'm getting really bad gas mileage for having a Golf (probably 20-25 mpg, depending on type of driving), it seems like there is a lack of power during highway driving, and just an overall "lack" of power for a 2000 lb car with 100 horses behind it. it has the 1.8L 8v engine. The sensor is 20 bucks at the local parts store, so it's not a problem to get one, I just want to try and narrow the problem down. Thanks!

 

yes, a bad o2 sensor CAN make you have bad gas mileage. If its bad it will tell your computer to mix the air/fuel wrong and CAN make your mileage go bad. Im not a professional but i do work on cars quite a bit so this is just my opinion.

 

I have a 1985 VW Golf and I am having terrible problems with hesitation, rough running and refuses to idle. All of this happens most of the time but not always. I've had one shop work on it for a couple of weeks. It now has a new distributor, cap, rotor, plug wires, coil, plugs but to no avail. They decided it was a fuel injection problem so we ran some fuel system cleaner through it which just seemed to make matters worse.I still think it's ignition. When I connect a timing light up the flashes are intermittent on three out of four plug wires. They even seem to be intermittent on the coil wire. It is fouling the plugs and spits black smoke. I'm now thinking it may be the electronic ignition control box but I saw your message about the O2 sensor. Did you change it and did it fix your problem? The cars not worth much and I hate to keep throwing money at the problem.

 

As I stated in an earlier post I've been having terrible problems with my 1985 Golf 1.8. It was running rough, refusing to idle and sometime running on what seemed like one cylinder. I spent over $300 with one shop and it only semed to be worse. Well I finally solved the problem myself. It is now running better than it has for the past year. Most of the ignition system has been replaced and I'd run a bottle of fuel injection cleaner through it but all for naught. I finally decided to check the vacuum system out. I found the vacuum accumulator was leaking so I block it off and then replaced all of the vacuum hoses, including the ones to the air box. Voila. It didn't fix it immediately but after a four mile run to the dog park it started running better. By the time I got home itwas running really good. It now idles and I can't believe how well it's doing. With the exception of initial start up, where it runs a little rough it smooths out quickly and goes like a Rabbit. I'm pleased, my dogs are pleased and I can't believe what $4 worth of hoses did for it.

 

wat if ur car isnt throwing the code for the o2 sensor? should u still replace it ? i got bad gas mileage to ..... i know my car leaks coolant could that be the problem?

 

no no coolant won't make you have bad gas mileage, unles it over heats real bad..ha ha. Yea you should every so often replace them, not as often as plugs, but ya know say 50,000 miles? I dunno for sure, just guessing. SO try that and if not let us know? What does your engine code say?

 

my car isnt throwing any code..... but i havent changed it since i got the car.... i got it used so i dont know if they changed it... Should i change it even if my car isnt throwing the code?

 

mmmmm if you're having engine trouble, or lack in power or anything like that then prolly yea, it would be a good idea cause like you said, you dunno if it was ever done.

 

i think i should cause my gas gauge wasnt working right for a while..... i had to start putting gas adictives ...... but i getting real low gas milage.....my car shakes when takeing off from first gear and the lights dim down a little ..... what could that be?

 

lack of power...somewhere in the electrical system.