I have 1986 Nissan 300zx car idles rough and rpm fluctuates

Asked by Jun 27, 2012 at 03:01 PM about the Nissan 300ZX

Question type: Maintenance & Repair

Up and down until the car wants to die. It only does this in Idle not in drive( 5sp) , as long as you give it
gas it will run but when it fluctuates this way it makes it had to kick it into neutral at a stop  light and
feed it gas to keep it running. Please help have changed plugs, wires, distributor cap and rotor button.
New air filters in car as well.

8 Answers

18,475

Sounds like a classic case of bad or out of adjustment TPS (throttle position sensor). Some can be adjusted and others cannot, idk which type you have.

2 of 2 people found this helpful.

I dont know for sure which type I have but I have adjusted the Idle up and it runs but it still will return to the fluctuating idle and will about die ... Thanks I will try to replace the tps and see if that helps. By the way I dont know if it helps but I have the standard 6 cyl. in the car no turbo or anything.

18,475

yours should be adjustable, the screws are on a slider. I would try to adjust it first before spending the cash on a new tps. loosen the screws and with the car idleing rotate the tps. You should be able to tell a difference in the rpm's when you turn it. Here is a cool video about it: http://www.youtube.com/watch? v=LmgYPuJkUuY

5 of 5 people found this helpful.
40

I would check for Vacuum leaks and all Vacuum LINES,, for cracks etc ... ..THE TPS,, Is not YOUr Problem .. NOTHING to do with your symptoms also if its a Turbo... the FICD should be cheecked.. CHECK your Engione Codes ...

3 of 3 people found this helpful.

We have the same problem. The TPS has been replaced and there are no codes. Does anyone have any other suggestions?

105

I agree with jcesp vacuum leak also check the TBS plug for corrosion might not be getting good contact

10

I finally got my 1986 300ZX to pass smog here in California. New EGR valve fixed the NO problem, but it still had HC and CO way too high to pass. I found a great Smog Repair station on smogcheck.com and the mechanic found the problem to be corrosion in the plug that goes into the TPS. He cleaned it up and it passed just fine and it fixed the idle problem I had too. So, a little corrosion at the plug made all that trouble. It is usually something simple, especially in an old car like a 1986, corrosion will work it's way right up a wiring harness or battery cable where you can't see it.

1 of 1 people found this helpful.
10

Correction to my post. I found the Smog Repair Station on smogtips.com, NOT smogcheck.com. And I found all the reviews for them on yelp.com Don't want to steer anyone wrong. My mistake!

Your Answer

Add photo

Related Questions

300ZX

Looking for a Used 300ZX in your area?

CarGurus has 130 nationwide 300ZX listings and the tools to find you a great deal.

ZIP:

Search Nissan 300ZX Questions

Nissan 300ZX Experts

#1 Tom Demyan
Tom Demyan
Reputation 440
#2 Jamie Staples
Jamie Staples
Reputation 290
#3 dandyoun
dandyoun
Reputation 240
View All

Related Models For Sale

Used Nissan 350Z
52 Great Deals out of 1,206 listings starting at $2,899
Used Nissan 370Z
59 Great Deals out of 2,882 listings starting at $11,995
Used Nissan 240SX
13 listings
Used Ford Mustang
541 Great Deals out of 45,846 listings starting at $1,999
Used Toyota Supra
53 listings starting at $32,500
Used Nissan GT-R
5 Great Deals out of 514 listings starting at $31,800
Used Chevrolet Corvette
149 Great Deals out of 20,684 listings starting at $3,995
Used Chevrolet Camaro
243 Great Deals out of 31,194 listings starting at $369
Used BMW 3 Series
945 Great Deals out of 30,262 listings starting at $1,000
Used Mazda RX-7
64 listings
Used Mitsubishi Lancer Evolution
17 Great Deals out of 495 listings starting at $13,998
Used Mitsubishi 3000GT
85 listings starting at $2,999
Used BMW M3
50 Great Deals out of 1,361 listings starting at $3,800
Used Nissan Maxima
321 Great Deals out of 24,382 listings starting at $999

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.