so I bought a 92 VX hatchback yesterday, on the test drive i felt nothing strange. once I purchased the car, i drove it 45 miles home, the last 25 miles of interstate i noticed that while maintaining speeds on roads and highway(35, 40, 45, 55, 65, 70mph) the car would feel as if it lost power for a second then the power would kick back in. this isnt while accelerating, this is foot in the same position on gas pedal, and suddenly lose power for a second, then catches again and i resume my cruising, usually in that second of power loss, the RPMs would stay the same, and the car would gradually slow, as if just drifting. anybody have any clues to this? the car is supposedly only getting low to mid 40mpg's, so im thinking this may have something to do with it.
if you have over 200,000 miles it might be your o2 sensor, sadly, at least this is the exact problem I was having, and after replacing a whole bunch of other parts, and taking it to the dealer, I spent the money on an o2 sensor, and instantly it was gone, and this is one of the few problems that the computer doesn't pick up on, so the check engine light will not come on, or have a code for.
I didn't notice a big jump in mpg, what I did notice what that drivability increased greatly, that I was able to focus less on keeping the car going a single speed.
when I removed my bad o2 sensor, I found it was soot covered (like a rich burning spark plug, black soot) and it had a bit of a rattle, like something was busted off inside, I latter read that driping oil on the outside can damage an o2 sensor as well, so the design of having it right next to the dip stick is maybe not the best.
It's an ignition issue. Check that all your plug wires are fully seated on the plugs. If your valve cover gaskets (the ones that seal the spark plug tubes) are bad, oil can seep into the tubes and actually force the wire off the plug, but before it does that, you get a faulty connection.
If your wires are properly seated, check your plugs, wires, cap, and rotor button for wear. Look at your wires closely....there could be a date printed on them. If it is 1992, these are the same wires that came with the car and are 14+ years old. OEM wires have the date of manufacture on them. If they are this old, I would recommend spending the $50 and getting a set of NGK plug wires - they're the best. If all checks out, it's possibly your coil. It could be your ignitor, but the tachometer would be going nuts if that were the case.
As a last resort, I have had one incident where the problem described was from a bad ignition switch (the electric component that bolts to the back of the key cylinder).
thanks for that, pretty informative. i was going through the stacks of paperwork that came with the car, and last tuneup was done 2 years ago, but they didnt use the ZFR4F-11 plug, they used ZFR5F-11, is that a big deal? im going to try and find a set of the right plugs today, and while im at it do a nice big tuneup
Isn't it possible that this is just the "lean burn" kicking in?
Either way, after buying a used car it's ALWAYS best to perform a full tune-up on it. Plugs, wires, distributor cap, oil filter, air filter, fuel filter, etc. If you have another $170, get a new O2 sensor on ebay too.