Lionheart240

My car had been running ideal for some time now, but I hadn't changed the plugs since I bought it in November...so I thought I would do it.



So I changed the plugs with all NGK 9's, and the wires to some Taylor Pro wires. They're REAL thick. They came with the car. Owner gave em' to me.



Well, immediately afterwards I started having this low idle problem. If I move a few feet lets say, then let off the gas, the idle will drop real low to like 300-400RPM, then slowly catch itself and build back up to 700-800RPM at a perfect -15 vacuum. Sometimes it'll actually stall out though, which is understandable considering it is idling so low.



Here's one thing I think might be the cause.



To replace the front-rotor's Trailing plug, you have to move the throttle body to be able to access the plug, because it's like, pinned behind the oil-filler neck. You know what I'm talking about.



The rubber/paper gasket on the throttle body broke when I was taking if off, and here I was in my friend's garage, his mom just came home. Mazcare wouldn't have one till Tuesday, so the only choice I had was to use RTV.



Do you think I'm just having a bad vacuum leak that's causing that? I am going to call Mazcare tomorrow to try and get that gasket.



Within about 48 hours, after some WOT'ing on the highway n' such, my car started acting pretty weird. Turns out my plugs got fouled..whcih again leads me to believe a vacuum leak is causing it to run very rich.



That night I replaced the plugs with NGK 7's and 9's, as they should be, but then I started having this problem where regardless of gear, or RPM I'm at, if I boost any more than 4psi, it'll stutter really hard and not want to continue revving, so I have to let off. Then it back-fires a little bit.



Here's the simplified version.



- Car ran fine before.

- Changed plugs with all 9's and Taylor Pro wires.

- Throttle body gasket broke..couldn't get replacement..used RTV temporarily

- Car starts Idling low, then catches itself after couple seconds.

- Spark plugs got fouled next day.

- Replaced them with stock 7's and 9's, but kept the Taylor Pro wires.

- Now having boost hesitation probs.



I plan to buy the throttle body gasket tomorrow, and probably another set of plugs, or at least clean off the ones in there well with a wire brush. I'm assuming that initially, the RTV was holding up OK, but now it's leaking badly, causing it to run rich, which in itself might explain the boost-stuttering, if it's fouling up my plugs so quickly.



My brother keeps telling me he thinks it's one of the vacuum lines I have capped off for the "Poor Man's Non-Sequential" conversion that I did via the step-by-step walthrough here on NP...but I went through each step where it says what lines to cap, and all my the lines were still capped..so I don't think it's that.



What do you think?

Nospig

most leads wont work with the stock plugs and coils. Try the factory leads again and replace the gasket. If you must use different leads use ngk race leads or use ngk r6725-105 plugs.

rfreeman27

a) get the gasket



b) verify that the spark plug wires are going to the right plugs.



c) have a look and make sure that you did not knock any vaccume hoses loose. It can be tough to see sometimes (map, the 4 on the front of the UIM, etc)



To change the plugs you shouldnt have to remove anything. Go in from the bottom next time.



to change the wires you have to take the TB off, so you woulda had to do it anyways.



you should be fine with 9's all around.



if it still isnt working, get a visual spark check on each plug. Sometimes the wires can be bad, so dont count that out. try to remember to pull the FP fuse when you do it...

Bad Karma

Start with the area you were in...map sensor would cause those types of problems. Check that you didn't accidently knock that sucker off. Next check if TPS setting is still within spec. (check when engine is warm) Verify that you are getting spark to the plugs, make sure you have coils hooked up.

Lionheart240

What does the MAP sensor look like? Where is it located?



How can one ADJUST the TPS if it's not correctly set?

rfreeman27

your tps is fine.



the map sensor is mounted on the firewall directly behind the elbow.



get the gasket, and stop worrying

dgeesaman

When you install the gasket, inspect your throttle body for signs of the RTV getting into there. Hopefully there isn't any, but if it did it could foul the idle airflow pretty badly.



Dave

Lionheart240

I ended up making a paper gasket out of gasket-maker. Was a biatch, with all the odd shapes of the throttle body, but works like a charm from what I see.



Tell me what you guys think this may be, though.



If I first start the car, she idles perfect @ -16 vacuum while warming up, even if I rev a little, she'll be right there at -15 or -16, which is normal for me.



But when I'm driving, the idle will constantly drop to 300 or 500, and the vacuum will be reading like -12 or MAYBE -14, in which case @ -14 it's ALMOST right.



After a little while it'll catch itself, but in time for traffic, which makes daily-driving it a little more difficult now.



Regardless of whether or not I boost it, this happens. So I know it's not the fact that the BOV is atmospheric, resulting in no air/too much fuel. It's not as simple as that, I'm sure...why? Because it didn't do this before.



Today I turmed up the idle itself, and even at -12 it'll be at 700 or so, which is cool. IF it is actually at -15 or -16, the idle itself is now 1,000-1,100...but the low idle issue itself is gone..



I'm thinking I should turn it down just a bit, but the way I'm looking at this is...OK, it didn't ever do -12 vacuum before, ever. Now, regardless of where it's idling, the fact that it'll be either -10 or -12 at an idle bothers me.



Vacuum leak anyone? >:/