View Full Version : 40+mph car shakes violently with light gas


HumanNipple
05-24-2011, 02:07 PM
I can't say anything has happened to my car recently other than an oil change. I was driving back from class going up a slight incline and when my rpms got to 1500ish in OD everything started shaking. I first thought engine mounts but that doesn't fit, the car loses power, feels sluggish, back fires, and runs like crap. If I accelerate from a stop it pretty much drives the same as normal but if I go about 40-50 mph and tap it then I get the same problem, this also happens if I switch the tranny to D but it's not quite as noticeable. If I put the car in park and rev it then nothing happens, the car sounds smooth as butter. I removed my SLP mass air to see if that was the issue but the problem persisted. I'm kinda scared this may be a transmission issue but i'm hoping it's just some weird electrical issue. What do you all recommend I try next?

senicalj4579
05-24-2011, 09:01 PM
How do you know its not engine mounts or trans mount?

HumanNipple
05-25-2011, 12:37 AM
the engine pops and has no power and seems to have trouble downshifting

coolformula
05-26-2011, 06:24 PM
Could be a lot of things, need some more info to troubleshoot.

Any SES codes?
Bad gas?
When was your last tune up?
o2 sensors?
VAccum leak
Does it do it before its warmed to OT?
TPS sensor? (I had a bad tps do really funny things on a lt1 car, it messed up the trannys mind...easy fix)

HumanNipple
05-26-2011, 11:36 PM
Could be a lot of things, need some more info to troubleshoot.

Any SES codes? not curently
Bad gas? Shell gas
When was your last tune up? spark plugs could use a change, tranny fluid changed within 30k, radiator flush too, oil every 3k,
o2 sensors? Po138 has occurred before and kicks in a SES light every once in a while but has never made it do this shake
VAccum leak? don't hear leaks but this is a good suggestion
Does it do it before its warmed to OT? does it during both
TPS sensor? (I had a bad tps do really funny things on a lt1 car, it messed up the trannys mind...easy fix) dunno what a TPS sensor is

answers in quote

TurbopigB4C
05-27-2011, 07:27 PM
Are you still using the factory converter? If not you could have a PWM shudder if you did not install a pwm eliminator valve. Also even with the factory converter the valvebody has a valve that gets messed up and sticks causing tcc shudder. If the shudder is only happening when the car is going into OD which is what it sounds like I would bet its internal transmission or converter related.

67RSCamaroVette
05-27-2011, 10:17 PM
Are you still using the factory converter? If not you could have a PWM shudder if you did not install a pwm eliminator valve. Also even with the factory converter the valvebody has a valve that gets messed up and sticks causing tcc shudder. If the shudder is only happening when the car is going into OD which is what it sounds like I would bet its internal transmission or converter related.

+1. I was thinking the same thing. I have fixed the Ford explorer TC shudder on two occasions. Those things shake so hard it feels like the wheels are coming off. When does it backfire?

TurbopigB4C
05-27-2011, 11:20 PM
Drive the car in D instead of OD and if it does not do it then it is tcc related.

Nastyc4
05-29-2011, 02:00 AM
Is it more like a bucking and jerking when holding the throttle open lightly? I have a similar issue Im still diagnosing. i got lean o2 code from 1 02. Im still trying to narrow it down to exhaust leak, failed cat or bad 02. Probably didnt help much but was more curious as to what specifically is happening.

El-Ess-Won
05-29-2011, 08:45 AM
TPS = throttle position sensor.

A TPS did this exact thing on my buddy's DSM when it came unplugged accidentally.

HumanNipple
05-29-2011, 11:01 PM
Are you still using the factory converter? If not you could have a PWM shudder if you did not install a pwm eliminator valve. Also even with the factory converter the valvebody has a valve that gets messed up and sticks causing tcc shudder. If the shudder is only happening when the car is going into OD which is what it sounds like I would bet its internal transmission or converter related.


factory converter, it shudders in OD and D

HumanNipple
05-29-2011, 11:02 PM
Is it more like a bucking and jerking when holding the throttle open lightly? I have a similar issue Im still diagnosing. i got lean o2 code from 1 02. Im still trying to narrow it down to exhaust leak, failed cat or bad 02. Probably didnt help much but was more curious as to what specifically is happening.
It's kinda of a bucking jerking loss of power kinda thing when the throttle is held lightly yeah.

TurbopigB4C
05-30-2011, 12:48 AM
Its hard to say then its could be a number of things. Best way to diagnose it is a Tech 2 if everything looks fine visually.

MattBrown0761
06-01-2011, 10:33 AM
your tires and wheels probably need balancing

HumanNipple
06-07-2011, 01:36 AM
your tires and wheels probably need balancing

...can't...tell...iff...being....sarcastic

HumanNipple
07-02-2011, 12:52 AM
finally got the car fixed, it was some majorly messed up spark plugs. One of them was coated in oil... but for now the car is running like a champ. I hope this doesn't happen again, i'll post some plug pics soonish

Roarin_8
07-03-2011, 12:05 PM
Plugs coated in oil? How much oil did you put in the car? You may have put too much.

HumanNipple
07-03-2011, 10:33 PM
2 were oily, unfortunately I had to take my car to walmart for my most recent oil swap. I was out of town and had no access to my tools so I dunno if they eff'd up anything

HumanNipple
07-03-2011, 10:42 PM
here's the plugs, they were pretty messed up IMO. Two of the plugs lost their tips inside their wires. They were Bosch platinum +4, they had those dumb 4 tip ends and they didn't work any better than the original plugs I had in.
http://i104.photobucket.com/albums/m184/HumanNipple/plugslabeled.jpg