Bad “jerking” during acceleration

[jrclark32]

I recently did a tuneup on my 1990 Festiva, 5 speed. I did plugs, wires, cap, rotor, air filter, fuel filter, and in-tank fuel strainer.

Since then, I’ve developed a totally new problem, which is somewhat intermittent. (Sometimes) If I take off quickly from a stop, as you do when pulling out into traffic, the car lunges and jerks in first and second gear. It kind of acts like someone learning to drive a stick who can’t quite figure out how much gas to give in 1st gear.

If I try to limit the amount of throttle I’m giving, it seems mostly okay, and I can get up to highway speeds.

Is it a fuel delivery issue?

I’d appreciate any advice.

[abarnett98]

Fuel delivery or maybe a weak spark. You might check over all the connections made regarding the ignition system, check spark plug gaps, and see how strong the spark looks. A lack of fuel could also cause some weirdness, yes. Might check fuel pressure. '90 Festivas are carbureted right? Might also verify the fuel filter isn't on backwards, I know I've been guilty of that more times that I care to admit. Best of luck to you.

[WmWatt]

Every summer I do a minor tuneup and every summer the engine misses afterwards. Misses show up on a tachometer or vacuum guage. I have the latter. Go over all your ignition wire connections and push on the wires to make sure they are snug. Don't know if that could be the cause of your symptoms. Good luck.

(PS 90's are fuel injected)

[redrover]

if you've checked the ignition and fuel delivery systems and still have the same problem - it could be that your VAF (on the airbox) is going bad

[jimdigs]

Bad “jerking” during acceleration. Thats what she said.

[jrclark32]

Thanks for the replies guys. I drove her a bit this weekend, and the issue has become less intermittent. It fires right up, idles fine, and I don’t hear a miss, but kick and lunge under a load.

It’s almost as if I’m occasionally losing spark entirely, and it’s happening in all gears now. I’m thinking it may be the coil or a connection issue with the coil wire.

I drove my truck today, but I should have some time to experiment tomorrow. I’ll try to make a video of what she’s doing so you can see/hear it.

[mexaspire]

It could be something as complicated and simple as a vacuum leak. I have spent numerous hours trying to find vacuum leaks on my Aspire.
Try disconnecting your MAF sensor and taking it out for a spin. Those seem to cause intermittent problems like the ones you are describing.