Gas pedal jerks/won't accelerate

My '92 Dodge Shadow (140k miles) refuses to accelerate. I’ll make it to 15 mph and the gas pedal will start moving on its own, tapping on my boot. I can let off and the next try will get me to 20 mph and so on, until I get it up to about 30 or 35. Seldom can I get over that. Once the pedal starts moving on its own, the tach just bounces back and forth between 500 and 1500. The car will be jerking and coughing, but it never actually dies. In between, it runs smooth. Any ideas?

Nobody has any comment, huh.

Well, hubby and I both suspect the transmission, especially after taking it for another drive. Only problem, it also hesitated in the above manor in reverse at similar speed. Check engine light is off, I’m getting no codes, plenty of trans fluid and fluid looks/smells fine.

I recommend posting your question here.

Do you have the 4 cyl or 6 cylinder engine? It sounds as if you have a bad engine miss which is causing the engine to jump on it’s mounts and shake the gas pedal linkage. Has the head gasket been replaced? They usually fail befor 140K miles.

I have the 2.5L 4cyl.

I’ve actually had the head gasket changed 3 times. First one at 99k miles. I’ve been driving with a bad one for four years now. I finally got fed up and decided I’d drive it, bad gasket or not, until it blew up.

You’ve had the head gasket changed three time! That says something about the person, or shop, which did the changing. The cylinder head may not have been milled flat (by a machine shop), the block may not be flat, if use-once head bolts, they may have been reused, the proper torque sequence and torque values may not have been followed, and the list goes on for how a job can be done wrong. One thing you can try: loosen all the cylinder head bolts, re-torque in the correct manner, and see if that brings any improvement.

I said it was changed three times, not that I paid three times or that it was the same shop. After the first replacement went out, the shop replaced it again for FREE. They took full responsibility, assuming they’d done something wrong. I probably would have received the next replacement for free too, but the shop had changed management and it was just barely over the 1 year anniversary of the change. So, I took it somewhere else. They fared no better. That one went too, like all the others, as soon as the next winter arrived. The first cold morning, I’ll try to start it, it’ll struggle, the gasket goes, I get a big poof of white smoke out the back and it’ll fire up and run fine after that. No one believes there’s even anything wrong with it, until I pull out the dipstick and it has foam all the way up it and then flip open the reservoir and show them all the oil floating in there. I love getting the “And it still runs?!” Four years and counting… that’s why I’m not quick to blame it on the gasket. That’s old news. LOL.

Just an FYI for anyone who comes along looking for info on a similar problem - turned out to just be the throttle position sensor. Cleaned it once, ran better. Cleaned it again and it’s been running fine since. Knock on wood.