Automatic 2.8 GTU Hesitating

[felixGTU]

So today I turned on my Beretta and it would crank and sound like it would start but as soon as I let go off the ignition switch it turns off. So I prime the gas pedal twice then start it again and it fires right up like it should. Then I was going to put the car on the ramps but half way on the ramp I would let go of the gas and the car would hesitate (sounding like it was going to turn off) and then it would accelerate itself. This problem only happens when the car is in first gear. after that it runs good.

Problem: Beretta hesitates on start up or when rolling off in first gear when hesitating car accelerates itself to compensate or it shuts down but starts right up. sometimes on start up it turns on hesitating so it will also accelerate itself.

Any help is very appreciated and thanks in advance.

[#1 stunna]

Its hard to diagnose these hesitating problems with our engines, when mine "acts" up , i always start with the basics = fuel and fire. Make sure you got the correct fuel pressure and that all plugs are firing... if all is good there then move on to computer controlled issues (sensors,egr,etc. and whatnot) Good luck

[SuzukiGhostRider]

Sounds like a possible TPS issue. Check all vacuum connections first to make sure you don't have a vacuum leak.

[3X00-Modified]

Also make sure the IAC is working, if it idles good warm then the IAC could be not opening enough when the engine is cold to give it enough air to idle. Cold startup is much richer so it needs that extra air.

[felixGTU]

I wanted to try something but wanted to ask first to know if it will work. I wanted to take some parts from my 3.1 Beretta and put them on the 2.8 Beretta to see if it will fix the problem. For example like the fuel injectors, IAC, and other sensors. My 3.1 Beretta is working great.

[3X00-Modified]

They should work... IIRC the 2.8 and 3.1 used all the same parts minus the crank it just had a longer stroke.

[felixGTU]

Okay so I have changed the TPS, IAC, O2 sensor, Spark plug cables, and spark plugs. Also checked vacuum lines. No change.

I know it still has the problem because when I put the Beretta in gear and apply gas and brake it start to hesitate around 1200 RPM. If I do this test in parking it does not happen. Could a transmission sensor be causing this problem? or is it something else?

[Styluss]

Simple initial check: Make sure that your throttle body is good and clean as well as the top plate for the throttle body. Just having this dirty of clogged can cause all sorts of problems. But like Stunna said, it can be one of like 15 different things when these engines hesitate or stumble. You can also try an idle relearn, that's free too. Have you had the battery disconnected recently?

[felixGTU]

Throttle body is clean and Battery has not been unplugged for a while until yesterday when I did a idle re-learn which also did not help.

[Money pit Beretta]

Is this one of those TCC problems?

[3X00-Modified]

first off, what do you mean hesitate at 1200rpm? Your in gear and on the brake, the torque converter is stalling then and stopping the engine rpm from climbing any further....

As far as a TCC issue, those typically will completely stall the engine out after the converter is locked up driving, it wont unlock coming to a stop sign or light and will stall like a manual transmission.

[Money pit Beretta]

Ah yes, well no posting for me after a big party weekend.

[felixGTU]

I'll post a video later today hopefully the sound can be captured on camera.

[felixGTU]

So the problem still exist. I did a cold idle relearn today and started good like it does let it go through one cycle (until fan turned on) and waited five minutes, went to start it again and it would not start. It was a crank no start. Waited till car cooled down turn it over and started right up. I have noticed that the interior light dim a little for no reason. Nothing in the car is on but the interior lights. Battery is good. Here is the video:

EDIT: In the video I ran the car for about two miles then shot the video so the Beretta is warm in the video.

[scd88ga]

Change your Crankshaft Position Sensor (CPS) It's either that or the Ignition Control Module (ICM) located under the coils.