Lumina, engine misses, and prob when damp

When I speed up, my car starts shaking , it?s not the front end, or a tire…

If I take my foot off the pedal it stops, then put it back to speed again and it shakes again. One mechanic said the fuel injector, and to put in injector cleaner in the gas tank. It?s been a year of injector cleaner every 3rd fill up and nothing different.

A friend started the car, opened the hood, and pulled off one spark plug wire at a time, the first two made a significant change in the motor behavior. The third wire shocked him… He then used pliars to get it off with, and the engine made no difference…

When it rains real hard, the car stalls whenever I go anywhere. Could this be all because of the spark plug wires? What aggravates me is I paid someone to replace the wires about a year ago. My friend says these wires are at least 5 years old. So, if that?s the case, should I also replace the spark plugs? Any advice would be great to this banjo player! Thanks

You should install new plugs and wires - no question about it.

Then report back if there are still issues after that.

Okay, I replaced the spark plug wires. The car runs AMAZINGLY after I am holding at a speed. While I’m accelerating, there is a very slight miss. It doesn’t do it while idling, only when accelerating.

Could this be the fuel filter? On a 95 Lumina how do I know what type it is?

If you’re not certain that fuel filter has been serviced on schedule then I’d replace it whether it helps this little miss or not. I’d also go for the air filter. Either one of these can be easily looked up at any auto parts stores. People at the counter an do it or there are these large reference books at various places around the store - you look up your car (year, make, model, engine) and you get ID numbers for the various filters & other things.

It also sounds like you did the wires only. I’d go for the plugs too - they’re not very much $$.

I’m so glad you posted this question. I’m experiencing a similar problem. My car skips very bad during a period of heavy rain or during a day of no use. I thought I was going crazy because my mechanic couldn’t figure out what was wrong. I also have to take my foot of the pedal and back on to stop the skipping tempoarily.

I replaced wires, plugs (several months before problem), and looked at the fuel filter. Finally, the mechanic replaced one of the ignition modules and that alleviated the problem somewhat. It still skips.

One thing I do early in the morning is to let the car warm up for about 5-15 minutes. I’m wondering if during this period any condensation that is built up on the electrical parts(module) is being dried up. That seems to help alot. I’m going to replace all the modules in the event one is cracked or just bad.

Let me know if you find a better and lasting solution.

Now… I’ve replaced the wires, plugs, air filter, fuel filter. The car runs 90% better. However… Still when I get around 50-60 MPH, it almost feels like when the car slips into that gear it still keeps rumbling… If I accelerate it shakes harder while its speeding up, then after about 2 mph it stops rumbling. OR if when it starts rumbling I take my foot off the accelerator and put it back… It doesn’t rumble. Also, over the past couple weeks, it seems to be shifting a little late. (auto trans btw)

Your truck sounds like it is still misfiring. Misfire could be from poor fuel flow, or poor spark. If your engine has a distributor cap and rotor, change those.
You need to check fuel pressure with the engine under load. A load can be applied to the engine by putting the transmission into DRIVE and running the engine rpm to 2000, for a couple of minuets while observing the fuel pressure.
Moisture may be problem on wiring, etc. Try a silicone spray on the ignition components (cap, wires, etc.). Silicone spray will block electricity (spark) from going places where it shouldn’t.
There may be a problem with the transmission. Check the transmission fluid level.
If the automation transmission fluid and filter haven’t been changed in a few years, if ever, doing so now MAY help with its performance.

The motor has 3 ignition coils, one coil for 2 cylinders. It could be that one of the coils has gone bad. Often you need more powerful spark under “load” mild acceleration as more fuel is put into the cylinders, a bad coil provides some current for a spark but not enough to fire the plug under stress.

Buy one new coil and replace the old coils one at a time. Eventually you’ll hit the jackpot and the car will run 100%. If it isn’t one or two of the coils you may have a more substantial problem.

Running with the misfiring so long may have caused some wear on the valves or the cylinder walls. Therefore a compression test may be needed to identify which cylinder has low compression. Once you know if you have good compression on all cylinders, or perhaps a couple of low compression cylinders then you can decide what to do next. Valve jobs and ring jobs involve a lot of labor and you may not want to spend the money on an older car.

Apparently, skipping and auto transmission problems must be common in 96’ Chevrolet Luminas. My car with 125,000 miles is shifting late from 1st gear to 2nd and will not shift into drive or reverse until I warm it up for a several minutes and press the gas pedal reving the engine. After that period it runs fine (ocassional slip at stop light). Let me know if your transmission problem worsens and steps taken to remedy it.

replaced an ignition coil and 98% is well… Now for the ORIGINAL problem.

When driving. I get to about 50 miles an hour. I let out on the accelerator to even off at 50… When the transmission levels out, (or sorta falls into gear) the whole front end starts shaking/trembling. When this happens, I take my foot off the accelerator and it stops. If I accelerate harder (through the rumbling) it rumbles harder for a few MPH increase then stops rumbling. But as soon as it levels off again, it starts rumbling.

I notice this at about 50+ mph never had it above 80. The trans fluid and filter have been changed within the past 5 months, and this problem has been going on for a few years. Several mechanics seem to be stumped.