88 Beretta 2.8L Automatic High Idle

sxsilver · Post by **sxsilver** » Sat May 12, 2007 4:55 pm

Hello,

My girlfriend just bought a 88' Beretta and I have been working on it to make it better for her. So far I have replaced the spark plugs, air filter, and fuel filter. I also fixed the exhaust but it was already broken in half.

She has been wasting a lot of gas. Before I worked on it she was using a tank a day. Now she fills up every three days. However, I noticed that it idle's about about 1800-2000 RPMS. I drive a manual and my car idle's at 800. I know an automatic should be higher but I thought that was a little high. I also noticed that when I was going 30 MPH and I let my foot off the gas the car stayed at 30 MPH and would not drop in speed.

I'm guessing there is a way to turn the idle down and was wondering if anyone could explain to me how to do it or if there was a guide online to do it.

Also if there is anything else I could look into so that she gets better gas mileage; please let me know.

Thanks

Post by **Cliff8928** » Mon May 14, 2007 12:32 pm

Actually the idle should be LOWER in an automatic. I would suspect either the IAC may be stuck, or possibly a vacuum leak somewhere. Is the check engine light on??

sxsilver · Post by **sxsilver** » Mon May 14, 2007 4:28 pm

Should be lower? Logically that doesn't make sense in my head but I don't know that much about cars just yet. In any case I disconnected the battery and re-connected it. It seemed to fix the issue. It now idle's around 900 RPMS. However i have noticed that when she stops the engine is still automatically giving it some gas. When your about to stop it revs the engine a bit but her foot isn't on the gas at all. I was wondering if anyone else has had this issue? I think it may hurt the brakes if I don't get it fixed.

Jeff P · Post by **Jeff P** » Wed May 16, 2007 7:36 pm

The throttle position sensor on the front of the throttlebody (lower) may need to be adjusted a bit. If you loosen the two screws you can turn it. As it is, the computer might think that the throttle is being held in a bit. Another thing that may help is lubricating the springs and stuff at the throttle linkage behind the throttlebody. Even just spraying it with penetrating oil is fine. If that doesn't fix the gas mileage issue, take a look at the oxygen sensor, as a bad one can cause a major drop in mpg.

Spiked · Post by **Spiked** » Thu Feb 28, 2008 2:50 am

I am not a genius with auto care, but I have a 88 beretta as well. I know that on the throttle linkage cable(think thats it) on the left side where yea can rev it, there is a tiny screw in there. If it is idling too high, you can back that screw off some. On mine it is some weird shaped key tool so I just use needle nose's carefully and back it out. Not sure if thats the problem, but worth having a peek at.

Money pit Beretta · Post by **Money pit Beretta** » Fri Feb 29, 2008 10:27 pm

Do what Jeff said first, the idle set screw should be the last thing you do. If you mess with it you could cause yourself more trouble down the line. The TPS isn't hard to adjust or replace.

SuzukiGhostRider · Post by **SuzukiGhostRider** » Sat Mar 01, 2008 9:54 pm

I almost guarantee you the TPS is no good or stuck. A very common problem in 80's and 90's GM and Ford cars. Cheap to replace. Just remember to set it when you install it. Usually ,when you install it , iirc , it needs to be pre-wound a 1/4 turn. Do NOT mess with the idle screw as warned above. If you do and later on you opt to replace the TPS and install it correctly, your idle will be screwed up again. You could always try to remove the TPS and clean it first of course. GL.

***EDIT*** Oops. My bad, just realized this topic was almost a year old. Sorry.

berettaspeed15 · Post by **berettaspeed15** » Mon Mar 31, 2008 6:24 pm

do NOT adjust the throttle plate trying to change the idle, please just dont. A new IAC would fix your problems i would think. Adding to the year old thread...woops! lol

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