In the past week, my Lumina APV has had a problem while driving. It does not stall, but it makes a clunking sound on acceleration. Any ideas? Please tell me it is not the transmission!!!

Have a look at the motor while you hold it back with the brake and give gas in gear. It might be rolling over due to bad roll restrictors or mounts. If you put the hood up and look under it from the driver's seat, you can watch to see if the motor pitches foreward and back too much. The restrictors on the front up top were easy to break on the older ones. Don't know what year you've got. But if the motor is flopping around, you're gonna hear some clunking!!

I have noticed tonight while driving my 92 lumina apv, that is seems to be lagging while driving, and the clunking has happened twice now while driving.

I have noticed tonight while driving my 92 lumina apv, that is seems to be lagging while driving, and the clunking has happened twice now while driving.

Did you check what I said? Are you missing power on acceleration from a stop, or anytime? If mounts are the problem, the motor is expending power producing unwanted movement, that can be felt as a loss of torque on acceleration.

Thank you for the reply, but no, I am not missing power on acceleration. It happens when I am driving. I am wondering if it is a miss in my spark plugs. I had a tune up in February, cost me over $400, and it seems that it has not run as good as before the tune up.

Thank you for the reply, but no, I am not missing power on acceleration. It happens when I am driving. I am wondering if it is a miss in my spark plugs. I had a tune up in February, cost me over $400, and it seems that it has not run as good as before the tune up.

Then the tune up is the place to start looking. Did you have plug wires replaced? Way back when, there were some service bulletins about possible inductive signal from the plug wires causing unwanted interference in sensor wiring if the wires were not routed in stock configuration. I'm still trying to make sense of your noise. Are you saying it is like a driveline lurch due to misfire or hesitation? Sometimes plug insulators can get cracked during installation, and a misfire under load is likely.

Check to make sure a plug wire hasn't sagged into something hot, like a heat shield or manifold. If you have a garage, watch the engine run in total darkness, and look for arcing.

I had someone test it today, and they say it is not the transmission. My rear brakes are almost metal to metal and the driver side drum is too thin and the passenger drum wont come off right now. After that is fixed early next week, I will check on that, Thank you. I am starting to think it is something to do with the plugs.
About checking that restrictor, I tried, my engine is set too far back to see it. It kinda sits under the dash.