Alright, one more shot

[Shaguar47]

I've posted this problem before but no one seems to know. So for the newbs and others who haven't seen it, I need help BIG TIME.

My problem is getting worse every month and is starting to really affect my driving. I almost ran into someones bumper.

Whenever I'm driving, say in 4th gear, and I let off the gas to decelerate, the car buckles forward and feels like it's loose. So once I'm decelerating and slow down to around 25-20 mph and stopping, the car then feels like it's holding on then suddenly it will buckle forward and backward like it's not holding on to the power no more. It just waves back and fourth, almost in a bouncing motion. So when I come do a stop and then start to move, I can gently press the gas or gun it and the car will bang forward. It's no smooth transaction from slow to fast or from stop to go. I can be doing 30, 45, 55, etc. and it does the same thing, It lurches forward when I hit the gas and buckles back when I let off the gas. Even If I let off the gas slightly or just drop it, the car will buckle back harshly.

So the other day when I'm following close to a car and they keep slowing down and gassing it, I'm trying to hit the gas as slightly as possible, but the car will lunge forward and I have to hit the brakes fast cause the I would almost hit the guys bumper. I've been told that the front of the car raises up and down when it lunges forward very high. Same goes for when I let off the gas as slightly as possible, the car will buckle back. It almost has a little hop to it when it does it.

I've tryed revving it up in my driveway, in neutral with my ebrake on the car does not buckle at all or the engine doesn't buckle at all either. It's smooth when I let off the gas and smooth when I hit the gas. So it's not the engine, but what?

Also, when I'm driving say 45 mph, let off the gas, car lunges forward and then hit the gas, the car will sometimes(only 3 or 4 times a week) skip. It's like I'm pressing the gas, but the car justs bounces forward. It's almost like it's not moving but is trying to but rattles the whole car. The whole car will shudder loudly and the whole chassis will rattlel like a tin can, then it'll move and it's fine.

I beg of anyone to help with this. It's getting worse and I have no clue what the hell it could be. Please, any ideas. I think I'm going to cry

[Figori]

Might be your front suspension. Get it checked out. Also, check your motor mounts. Sounds like one of them might be loose, and that would cause your car to buckle slightly. Almost sounds like the lower mount by the tranny.

[Shaguar47]

It probably is the suspension. It's just when I tryed it in the driveway, the engine never buckled or whatnot.

Any way to check the mounts for sure if their good or not? And where's the lower mount for the tranny? Actually, where are all the mounts?

[quiXilver]

Also I would check your transmission mounts. Maybe even your timing, my car does that shit when my timing is off, also did that when the transmission mounts were shot.

[Figori]

Hmmm. This should help a little. Like I said, check out that lower tranny mount, expecially if it's an automatic. The best way to check your motor mounts is to put it in gear, hold the brake and press on the gas. Slowly bring your rpm's up and see if the motor moves alot (have someone help you, and raise the hood). But, try it out and let us know what happens.

[Shaguar47]

Originally Posted by Fibori

The best way to check your motor mounts is to put it in gear, hold the brake and press on the gas.

Doing this while letting the clutch out, like I'm starting to move from a stop? Alright, I'll give it a try once I get off work and after I get my new goodyears put on today.

[Figori]

Okay, yeah... You have a manual..... Right, like your moving from a stop. Just make sure you have someone to watch for ya.

[Shaguar47]

Thanks Fibori, I'll give it a shot later today with my friend and we'll see.

But how much should the engine move, or should it move at all when trying this?

[TheSilentChamber]

Yeah definatly check the mounts. you can do it an easyer way though, With the engine off put it in first and dont put on the ebrake. Pop your hood and stand infront of it and kinda rock the car forward and backwards and see how much the motor moves. if it moves a whole lot you need new mounts.

It could also be a fuel problem. One time I seen this was someone had put some small round balls in someones gastank, it would fuck with the pickup tube when they slowed down and when they accelerated.

[civicHBsi91]

I dont see how it could be mounts, if they were so bad the motor itself would just move inside the engine bay and the car would not raise up like he was saying.

my car basically ran on two motor mounts, when i got in it the motor would hit the firewall and thats how it would stop flexing, not good at all but i still managed to run 14.7's and hit 2.1 60's with that problem and my car never had that problem as stated.

[Shaguar47]

Well, I got with one of my buddys and did this. I pulled up against a parking curve, started the car, pulled the ebrake up, stuck in first and started to let the clutch out and gave it some gas to keep it running. My friend said that the back of the engine, where the DPFI box is, really dipped down alot and looking at the valve cover, the engine didn't move alot but did move. He said the back part was more noticable and that it moved maybe about an 1" 1/2. We even looked at his car, a 91 mazda protege and compared the two, and mine moved alot more than his did. So what do u guys say?

Also, I forgot to mention. When the car does jerk back and forth, u can feel it in the shifter. I don't know if my shifter should be really wigglely when in gear and moving, but you can see it shake when the car jerks or bobs.

Now, what could it be?

[Figori]

Get underneath the car and check your transmission mount (It's on the back of the transmisson/differential). See if it's damaged/broken/loose. It's a good place to start.
[edit] Also, try the same test, but with reverse. That will allow your motor to flex back up. Just a good way to check everything.[/edit]

[sastanley]

the shifter is connected to the tranny, so it is in essense part of the engine assembly. It should flex a little (mine moves 1/4 - 1/2" when I step on or off the throttle) - this is a natural movement related to the application of torque when stepping on the gas. However, it shouldn't be extreme.
Check out the link to the pic a few posts up from Fidori again. The engine has one big mount on the driver side to the frame, and the other three are located on the tranny. If any of these are bad, there could be some issues. Also, check your throttle cable and make sure it is not too tight. It should have the tinyest amount of play in it. If it is too tight, it might also make it hard to have the smooth transition from gas on/off but again, it shouldn't be that extreme with only 70hp (STD) or 92hp (DX) under the hood.
V8's make the front half of the car twist dude...and you think your engine is acting torquey

[Shaguar47]

Originally Posted by sastanley

it shouldn't be that extreme with only 70hp (STD) or 92hp (DX) under the hood.

Your right, it shouldn't be extreme but that's what it is. I'll check the back tranny mount tommorow and see how it is. And I've tighten the throttle cable a few weeks back but It still has a little play in it, and I've had this problem going on for almost a year now so I'm pretty fed up with it.

I've been thinking but could the dashpot, pcv valve or even the cat. do this?

[88ReX]

I would definitely check your tranny mounts. From what you describe this is exactly the problem I had and I never figured it out until I was underneath the car one day and notice that my front tranny mount was not bolted to the front end at all, I found some bolts, put them in and the jerkiness was greatly reduced.