Car is bucking when cold

[Pozobyt]

(I have tried searching and can't find anything that really matches my cars symptoms, that isn't a turbo)

When I first start my car and try to drive it, it will start and idle fine, but once I put it into drive, sometimes it will just stall, and other times, when I accelerate the car will buck and jerk really bad. Once I drive for a couple minutes, it is fine and doesn't give me any more trouble, and if I turn the car off and on again while it's still warm and drive, it's fine.

plugs, wires, and coil are all new. no CEL.

help?

 

[gudz519]

sounds alot like a vaccum leak

 

[jaydubb1988]

Check the collent temp sensor it sounds similar to what my car was doing and that was my problem but I had a cel and I had to do the 12v buzzer test thanks to obd1 haha hope it helps good luck man

 

[Pozobyt]

I'll go get my codes checked tomorrow anyway just in case there's one stored and the light isn't coming on for whatever reason. And now, today it started doing it when it was warm, so Idk.

 

[pgarland]

Hit some of the basics...clean the throttle body and Idle Air Controller (super easy to remove and clean, should only take a couple of minutes), and take the EGR off and clean the heck out of it (carb cleaner will work, but be prepared to use at least an entire can, and also be prepared to see a large amount of sludge come out!), see if that helps at all. Like jaydubb1988 said, it sort of sounds like a vacuum leak, but I'm leaning more towards the EGR just being gummed up and filthy because you said it doesn't happen (or happens much less often) when the car has properly warmed up. The EGR is supposed to be closed when the car is cold and at idle, so if it is faulty and is actually open at idle (a filthy EGR can cause this to happen), it'll act like a huge vacuum leak, and cause some of the issues you mentioned. A dirty EGR won't necessarily throw a CEL either, so this might explain why your CEL hasn't come on yet. Give this a try, and let us know the results.

 

[murray1]

Sounds like upstream oxygen sensor to me. Had something similar happen with my car.

 

[Pozobyt]

Okay, I'm not throwing any codes, and I actually recently cleaned the throttle body, IAC, and the egr, so that wasn't it. I did find one vaccum leak coming off of that line that is on the throttle body, and I fixed that, Still no change. And now recently, EVERYTIME I put it in drive or reverse it stalls out. I can kind of keep it running in drive if I hold the brake and gas down at the same time, and then shift it. but when it starts to stall, I have to floor the gas to get it to stay running. And when I do get it to stay running in gear, it bucks a few times, then stalls. my thoughts are possibly:

1. TPS?
2. Torque converter staying locked up when I'm shifting into drive, then locking and unlocking, causing the buck?
3. Upstream O2 sensor like he said, but it's not throwing a code?

 

[murray1]

3. Upstream O2 sensor like he said, but it's not throwing a code?

O2 sensor doesn't always throw a code, as I found out with both my 97 Talon and 91 Escort.

You can probably test it instead of just replacing it but I am not sure what the acceptable values are.

 

[LD25Delta9]

+1 on the Coolant Temp Sensor. Also check the VSS (Vehice Speed Sensor)