Hey all,

So its been quite some time since I have posted on here and this time around I have a doozy.

I have an 88 IROC with a rebuilt 4 bolt main that has been upped to a 383. Holly Stealth Ram, BBK 58mm Intake. (Note: All smog equipment has been removed in hopes of solving below issue, but no luck there).

There are several issues going on here, however I believe they are all related. The one that stands out the most is when drive is engaged and you are not moving. The engine will soon begin to drop in RPMs and then surge back to idle speed and then down again, ect. Then after a short stint of surging, then engine will miraculously cure itself and stay at idle speed. Then after a short while the surging will begin again. Also note the batter meter, and RPM meter in the gauge panel will drop and surge in sync.

I have video of the gauges doing this if that helps for a better diagnosis.

The weird part is this was happening before I had the above mentioned engine work done. So I have a feeling this is something more along the lines of electrical, but all the mechanic as I have dealt with either cant find the electrical issue or don't want to even touch the car. I am not a mechanic, but am willing to do what I can, just not sure where to start looking at the moment or what to suggest to a mechanic.

Thanks in advance with any help you can offer.

 

I'm under the impression that a vacuum leak could cause a surging/dipping idle. The battery gauge lowers because the output of the alternator is dropping when the idle dips down.

 

Any ideas on what to check then (Gaskets, Hoses, Ect.)? I saw in other threads that sound similar to my issue to use a water to look for a leak, but need to be careful of the electronics.

Its a new alternator and battery, and when starting cold the battery meter is right in the center, however after a few minutes and getting warmed up the needle tends to drop to the lower line and even on occasion sits right above the bottom red line.

Also another symptom that has not occurred of recent, but dose on rare occasion, is when I am traveling at freeway speeds (65mph), then go to WOT, the engine drops to what feels like idle and then right back to WOT. It’s only for a split second when it does occur and will only do it once during that particular acceleration.

Just more food for thought.

 

Here are some pics of the engine if this helps.

 

when i was having a similar issue i found it was my fuel injectors biting the big one