Unknown Idle Issue (?)

[Bleakened]

Hello, ClubCivic peeps. This is my first post here and before I ask my question, I'll let you know my civic I have is my first car and I don't really know too much at all about anything under the hood of a civic.

I have an automatic 98 Civic DX hatch, stock D16y7 I bought from someone on Craigslist and it had a ton of small issues that I have already fixed but one large issue that didn't show up when I looked into it before I bought. (I got burned, I know.)

So when I'm idling in any gear at all, hot or cold engine, I feel "hiccups" come from the engine and it vibrates the car just once. Like a jolt. Kinda sounds like a misfire to me. When it does, it drops about 50-100 RPM (tested with a scanner from a friend) and you can actually see the engine jump a wee bit when it does it in park/drive with e-brake on. It does it continuously forever when not moving about every 2-4 seconds.

Me and a mechanic friend of mine who has an ASE cert. can't figure out what the hell is causing these hiccups. It's not a huge issue as it doesn't do it when driving but it still shouldn't be doing that.

So is it time to do a swap or is this a cheap fix? I'm on a budget and don't plan to tune it very soon. Just my daily driver.

Checked the spark plugs, they're pretty new and still shiny.

TL;DR, engine hiccups when idle, what should I do?

 

[CO671]

How about the spark plug wires.
I'd start off with checking for any vacuum leaks.
If everything's getting good spark, the timing's right on the dizzy and the timing for the cam/crank timing belt.
If it's not any vacuum leak, spark plugs/wires, distributor, dizzy timing, belt timing, it could be sensor related.
IACV, TPS being the first two culprits.
No CEL?

 

[Bleakened]

How about the spark plug wires.
I'd start off with checking for any vacuum leaks.
If everything's getting good spark, the timing's right on the dizzy and the timing for the cam/crank timing belt.
If it's not any vacuum leak, spark plugs/wires, distributor, dizzy timing, belt timing, it could be sensor related.
IACV, TPS being the first two culprits.
No CEL?

No CEL, nope.

I haven't checked anything else you said but I don't know what half of what you said is.

How can I check for sparks? and I have no tools to check the timings on anything. I do know the spark plugs are good though, almost new. What is the TPS? And IACV I'm going to check tomorrow.