Beretta.net

I have a 93 beretta gtz 2.3L quad 4. it stumbles at idle. when I accelerate slowly it doesn't have a problem accelerating. when I accelerate at a medium or fast pace it stumbles. I just changed the cps and the IDI module. all the wiring has been checked and is fine. I have plenty of fuel pressure. it doesn't seem to be the injectors either. any help?

What exactly is the module you changed?

I changed out the ignition module cause it was shortin out. today I changed the coils and the tps and I'm still having the same problem. I'm able to accelerate slowly and it does alright, but when I accelerate at a medium to fast pace it stumbles. the fuel pressure checks out ok but right now I'm at a loss as to what is causing the problem.

My guess is on the coil cover if it's ignition related. They should be readily available and around $45.

it's not the coil cover. when I have the key on engine off, the map sensor reads 29.3 vacum and 4.78v. when I start the car the vacum drops to 10.3 vacum and 1.28v. I've put a vacum gauge on it and it says that I've got 19in of vacum at an idle and when I rev up it goes to 25in vacum. but the computer still reads 10.3 on the map. I've checked all wires and sensors but I'm still not having any luck on getting this car to run right. any ideas?

well it wasn't the coil cover. I changed the ignition control module, coils, spark plugs, throttle position sensor, knock sensor, map sensor. I've checked for vacum leaks, fuel preasure is fine, I even changed the ECM. still no luck on gettin this P.O.S. to run right. I'm outta ideas as to what the problem is. I'm out of resources and ideas.

What trans?

it's a 5 speed manual trans axle... FWD

Have you checked/changed the crank sensor, and or double checked the timing chain setup to ensure its not loose enough to be off.

I've replaced the crankshaft position sensor already, I've checked the timing chain as well. I believe that my prom chip went out so I do have one on order. will replace that and see what happens.

You changed the ECM but swapped the prom over?

I've tried 3 ECM's and used the same prom, and it didn't solve the problem. I have a prom chip on order, just waiting to get it in.

Yeah, all the ignition control and such is on the prom so yeah that might have been the issue all along... or hopefully for you it was.

You know I've done about all the same but I didn't let me fuel pressure tester sit for a few minutes to see if it holds pressure fine and it doesn't. So if your prom doesnt fix it give it a minute I'm not sure yet what it could be if its the fuel pressure regulator blatter on the vacum lines or the fuel pump.

Does that thing have a TPS (throttle position sensor) at all? Just wondered if it flakes out when positioned past a certain point....