Intermittent bucking / hesitation !!! - SRT Forums

Spicoli · 07-15-2008, 07:03 AM

With just over 40k miles I’ve started having problems with the car losing power and bucking wildly at neutral throttle settings and at varying speeds. It’s happened in 3rd, 4th, and 5th gears and will go away as soon as I mash the throttle.

Here’s what I’ve checked / replaced. Checked intake manifold gasket (visually), checked TPS wiring (Wiggled connector while engine idling with no apparent RPM change), replaced plugs and gapped correctly, replaced wires, cleaned and re-oiled K&N. Thought it was a tank of bad gas (H2O) and went through two bottles of dry gas. No luck.

I have S2 w/o toys and have never had any issues with the car. With new plugs and wires it pulls so very hard in every gear and runs very strong. It’s just when you cruise at any speed and just maintain a low throttle setting it develops this bucking.

The symptom is very similar to when someone is just learning on a manual transmission and doesn’t work the clutch and gas right and comes close to stalling it.

I’ve searched the forums and can’t seem to find exactly the same symptoms. Looking for any help or direction. With S2, don’t want to take it in to the dealer (I do have an extended warranty) just yet; and not sure if they would honor it with the S2.

One thing I haven’t checked / replaced is the coil pack. I know that takes a lot of heat from the turbo but it’s so damn intermittent and runs so strong otherwise, it’s hard to believe it’s the coil.

Thanks for and feedback !

XxWicked_MagixX · 07-15-2008, 11:59 AM

Do you have solid motor and tranny mounts?

My car does the same thing...

Spicoli · 07-15-2008, 12:04 PM

Nope. stock motor and tranny mounts.

04electricblue · 07-15-2008, 04:17 PM

I'd say it isn't the s2, but who knows on yours. I am stock 100% (okay I lied a BOV and stereo thats it!) and I have some nasty bucking/stumble/hesitation upon WOT in 3-5th gear. any ideas... I just checked the plugs ( I have 31k) they all look okay, nothing jumping out at me, wires are fine... NEXT!!!

Spicoli · 07-15-2008, 06:36 PM

Ok, driving home from work was brutal. Bucking, hesitation, and at times absolutely no power at all at any throttle postion. Thought I would have to pull over several times. Then it cleared up after maybe 30-40 seconds. Only 13 miles from work to home thank God.

I got home and let the motor cool down. Checked everything out and noticed the coolant line that feeds the turbo had a small leak right where the hard line goes to a rubber hose. This juncture happens to be right above the cam sensor and it must have been dripping on the cam sensor plug and there was a ton of pink colored corrosive buildup in the plug itself.

Pulled the sensor and cleaned it and the plug connections, reinstalled, added a touch of di-electric to the connection and reattached.

Oh and put a worm type hose clamp on the line to stop the small leak.

test drove just now and no hanging RPM's and no bucking or hesitation. I'm not out of the woods yet though casue it acted fine right after replacing the plugs and wires.

Anyone have this leak drip onto their cam sensor ????

Michigan_SRT · 07-16-2008, 12:04 PM

Quote: Originally Posted by Spicoli

Ok, driving home from work was brutal. Bucking, hesitation, and at times absolutely no power at all at any throttle postion. Thought I would have to pull over several times. Then it cleared up after maybe 30-40 seconds. Only 13 miles from work to home thank God.

I got home and let the motor cool down. Checked everything out and noticed the coolant line that feeds the turbo had a small leak right where the hard line goes to a rubber hose. This juncture happens to be right above the cam sensor and it must have been dripping on the cam sensor plug and there was a ton of pink colored corrosive buildup in the plug itself.

Pulled the sensor and cleaned it and the plug connections, reinstalled, added a touch of di-electric to the connection and reattached.

Oh and put a worm type hose clamp on the line to stop the small leak.

test drove just now and no hanging RPM's and no bucking or hesitation. I'm not out of the woods yet though casue it acted fine right after replacing the plugs and wires.

Anyone have this leak drip onto their cam sensor ????

Where exactly are you talking? This could be my problem... same issues

Spicoli · 07-16-2008, 12:58 PM

At work now and can't take a pic. Can't find one quickly in the FSM either. So I'll try to describe where it is.

Standing in front of the engine, the cam sensor is on the right side of the head near the top. It's round and black (about 2.5" diameter) with an electrical plug facing downward. The wire connector plugs in from the bottom. The connector is hard to see as it is hidden by the stock air intake running from air box to turbo. The leak was right where the hard coolant line (that runs from the top of the compressor section forward along the side of the motor) transitions to a rubber hose (and just above the cam sensor ) that then turns down and back towards the firewall to (I'm assuming) the heater core in the dash.

Any one to add pics would be greatly appreciated. If you have this same problem you can’t miss it as you’ll see pink fluid corrosion all over the plug.

Drove fine to work today but I'm still waiting to see if this cleared it up. If it does not completely, I'm looking at replacing the cam sensor before the TPS. I don't think the TPS is my issue. Plus cam sensor is cheaper when throwing $$$ at the problem.

jay04srt4 · 07-18-2008, 10:16 PM

I re wired the black wire on the tps wire. Read the sticky here about the 3k rpm hold up. prolly ur problem