Car: 90 Laser RS (4g63t if you didn't know)

When I try to cruise at a certain speed limit the car is doing fine for a few sec. to a minute then begins to hesitate... gets jumpy... feels like its rocking forward and back then when I give it a little bit of gas it goes away. If I give it gas I don't notice anything except here and there feels like a backfire. If its sitting while idling same thing happens here and there it backfires. Now I haven't checked the spark plugs but the wires looked to be new and their in all the way. I do have a replacement coil pack that I have to install. But I'm wondering what this could be before going into any extent. Don't know how long the car has been sitting and if its been driving a lot or seldom in the last few months. When I bought it, it almost at empty (gas wise) so I filled it up with 93. Could it be that its been sitting so long that I'll need to run a Fuel System Cleaner (pour the bottle in my gas tank)? Any help is appreciate. Its boosting fine at stock boost.

My quick question:
Whats the recommended gap for the spark plugs?

I don't have time to research it since I'm at work and I'll be working on the car right when I get off. Stupid question I know but the sticker is missing underneath my hood which tells you also my Haynes and Chilton manuals are packed somewhere in one of my moving boxes and I can't find them.

 

lol, when i had bad lifter tick, the knock sensor was pulling timing from it. it would pull about 12 degrees of timing and would feel like it was being held back and backfire once in a while.

 

Well the lifter tick is during a cold start up and about 2 minutes later or so it disappears then when its warmed up it starts doing what I mentioned above but the lifter tick is minimal... like I said just during cold start up. But I managed to do some research while at work and it could possibly be the spark plugs according to a few DSM FAQ I ran into. Spark plugs can cause the stuff I mentioned above and them being gapped wrong. So I'm going to pick up the right set of plugs whether the car has the right ones or not. I'll gap them and put them in then see what happens. That will be my mission when I get off of work. Hopefully thats the cause.

 

ya thats a good idea, and they are cheap and easy to replace, so nothin to lose there

 

The spark plug / wires should be brand new (and I did the gap according to the Haynes Manual). You do know that the wire connecting to the knock sensor is cut right? (the ecu is not reading any knock) I never drove the car far distances due to not having it registered as you already know, but it was started up at least once a week.

 

The car seems to have a high carbon build up. Jon, the spark plugs are brand new I could tell when I pulled them but they were black as can be (carbon build up). There's a lot of carbon deposits coming out of the exhaust, turning the bottom end of the bumper black and leaving a streak of carbon on the driveway. The spark plugs were gapped at around .032 which is fine according to sources I found. The spark plugs I put in were the same kind I took out but I gapped mine at .028 which is according to the manufacturer. I did keep the ones you put in Jon. I'm going to clean them and re-use them. I went ahead and cleaned out the throttlebody it was nasty and the plate was slightly opened (could be the reason why it idle high). I sprayed the intake cleaner and started up the car took if for a drive... smoke came out of the exhaust for about 3-5 minutes and hesitation slowly went away. The smoke went away car felt much better with minor hesitation unlike before. I'm thinking I need to run a FISC (Fuel Injection System Cleaner) which is directly flowed into the line of the pcv valve to clean out that heavy carbon build up. Also buy a bottle to put into the gas tank. Thats the only explanation I have for it... carbon build up. Jon, I am aware of the knock sensor wire being cut I have not had a chance to replace it with the new one you bought and gave me. But hopefully I can change it tomorrow ( I took off from work) or this weekend.

 

ya replace the knock sensor, thats just asking for trouble

 

What tool is needed for that and whats the easiest way to get to it?

 

Never mind I found the information. It seems it will be tuff to get to with the head on the car but still be able to do it with it on.

 

yea i just used an adjustable crescent wrench since it is shaped like a bolt, just takes a litle time. now i have seen special sockets made for o2 sensors and stuff, maybe you can find one of those in the size you need. they have a slit in the side for the wire to go out of.