Help with my 93 J30t

[jldyer]

Gentlemen...and ladies...

I've been lurking in the background till now, searching for the answer to my problem. But I haven't found anything that has worked...yet. So now it's my turn to 'stump' you all.

Problem: Intermittent sluggishness accelerating after car is warm.

Details: The car drives nicely when started in the morning. I drive side streets till I get to the freeway...runs great, even when warmed up. Freeway driving is excellent. I drive about 30 minutes at 70 mph. Acceleration is very responsive, even though it's warmed up. If I have to stop or slow down near the end of my freeway driving, that's when the sluggish acceleration begins. Press accelerator, rpms move up, but car doesn't respond immediately (like it does when it's cold in the morning). If I'm accelerating from a stop, it goes slowly for maybe 5-10 seconds and then picks up speed faster. When it shifts to the next gear I can feel it lose power and then pick up again after 1-3 seconds.

When I tried to get the car smogged (before I did ANY of the stuff listed below), the car failed on HC (My car: 1.7 gr/mile, Allowed: 1 gr/mile...inspector said it's a misfire) and CO (My car: 61.69 gr/mile, Allowed: 12 gr/mile...inspector said it's running rich). After all of those changes, HC's passed. CO's are now: My Car: 18.33 gr/mile, Allowed: 12 gr/mile.

What I've done so far:

• Replaced MAF
• New spark plugs
• New air filter
• New battery
• Changed transmission fluid
• Redline
• Always run 91 octane...running 94 octane now

Possible causes:

• Oxygen Sensors?
• Your ideas here...

If you need more info, let me know. I'd like to try getting it smogged again today, but I'd really like to get this issue fixed before putting another $30 down.

Thanks...

JLDyer

[fourdrinie]

You might want to check for a po300 code...one of your coil packs might be dead or misfiring..
Find. Replacement coil pack and keep substituting it in different positions looking for improvement.

[jldyer]

Hi fourdrinie...I have NO codes. I had it resmogged last week after all the things I did and HC is now below the limit and CO is much better...but still failed.

I cleaned the throttle body last night and found two hoses that were split that I replaced...but I still have the same symptoms.

I ordered two new O2 sensors and will post my results.

[fourdrinie]

How long was the car running prior to getting the last smog test?
Many people here have taken a long trip (at least 1-2 Hours) to really get the cats hot! Then it passes!

[jldyer]

I drove it on the freeway for about 45 minutes before I went in, and I left the car running while in line.

[fourdrinie]

There is that possibility that your cats are "wearing out"
Is there a smog station like the gold ones here in CA that can isolate each part to determine the culprit?
Might be costly, but time saving and beyond keep throwing parts at it

[swimshark]

get new coolant temp sensor for ecu (the 2 pin one). it is most likely gone bad and out of tolerance. try that first.

http://www.z1motorsports.com/product_in ... ts_id=1723

[jldyer]

I replaced my oxygen sensors yesterday. It was much easier than I had read on the forum. It definitely has made a difference. I want to drive it a few days before I go in for my free 're-smog'.

Swimshark: If the O2 sensors didn't fix it, I'll change the temp sensor...$25 is a good price. BTW, what's the electrical blade connection right next to the coolant temp sensor? When I first started working on this car, I found the wire had broken off. So, that was one of my first fixes. Just curious.

fourdrinie: If the O2 sensors and the coolant temp sensor don't fix it, I'll look into the cats...I pray it's not the cats.

Once I get this things to pass emissions, I can focus on the suspension...I need to replace the struts badly! And I might have a bearing in one of the wheels going bad. Anyone know how to test the bearings to know if they are going bad? I have a low rumble that I hear, but was thinking it could be the struts or the tie rod ends.

Thanks for the help...love this forum.

[chiken7]

hey if you end up needing additional coils, i'll send it to you for free; just the shipping cost for you.
I have 1.

[jldyer]

Changing the O2 sensors and cleaning the throttle bodies worked...

I passed emissions!

I still think I'm going to change the coolant temp sensor and replace the plug that connects to the top of it...a piece of the plastic is broken off, so it doesn't snap on anymore.

Thanks for all of the help on this one.

Next project...replace the rear struts.

[yodawill2000]

Rear struts are a snap.
I'm using 240sx rears and they bolt right on.
Cheap too !

[fourdrinie]

congrats!...wasnt as bad we thought....

[jldyer]

I got 19.97 mpg on my last tank of gas. That was mostly freeway driving. Is that good? or could I get better?