Sudden loss of power with 93 nissan pickup.

[Anthony]

This truck is a 4cyl ,and has always run very well.
I bought it with 98k ,and its currently at 161k.

A couple of days ago I installed new NGK V-power plugs, NGK wires, a new cap ,and rotor ,and a fuel filter.

All of this is basic stuff ,and very easy to service on this truck.

For some reason after this was done it has lost a lot of bottom end power.
I cant figure out how anything I did could be linked to it ,but that is when it started doing it.

When the truck is cold it feels just like it always has, Once it gets up to temp, it is not nearly as responsive from a stop as it once was.

It dosent seem to be misfiring ,and it starts very easily ,and idles perfectly.

Any ideas? Thanks.

 

[Towncivilian]

You used NGK ZFR5E-11 (4435) plugs and gapped them correctly (0.039 to 0.043 in)?

Is this truck 4WD with a manual trans, by any chance? There is a TSB that states to overfill the transmission because the original quantity is wrong.

 

[Eddie]

Hmm: runs ok cold but, power loss when warm. You replaced distributor cap-did anything fall into the guts of the distributor or did you rotate it? Next I'd look for a vacume hose leak.

 

[OtisBlkR1]

Originally Posted By: Towncivilian
You used NGK ZFR5E-11 (4435) plugs and gapped them correctly (0.039 to 0.043 in)?

Is this truck 4WD with a manual trans, by any chance? There is a TSB that states to overfill the transmission because the original quantity is wrong.


plug gap was my emediate thought as well, ive seen some wrong gapping before that only effected MPG and mild performance, car still started and idle just fine.. this is where i would start. any odd noises, spark knock ect ?

 

[Scotty59]

Check your front calipers out, they could be sticking ie, not releasing. Had the same truck a few years back, went over a bridge that was being resurfaced, and my rotors locked up almost to the point of not being able to get it off the road. After some gymnastics along the street I finally got them to release. But afterward they would drag, so replaced with rebuilds and new pads. End of problem. Hope you find this helpful.

 

[mopar_monkey]

i had this issue with a 93 nissan pick up i had, same thing after i did a tune up it didn't have as much pep, then after time became worse to the point that the truck was almost undrivable, ended up being the rotor, from what i found out these trucks have 3 possible distributors they can be equipped with and the rotors are very very slightly different.

 

[Merkava_4]

^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

I'm thinking you may have just saved the OP's day right there.

 

[Anthony]

Thanks for the responses!
One thing I didnt mention is that I did replace front rotors , calipers ,and pads as well as repacking the front wheel bearings the same day I did the tune up.

Town civilian, I did use NGK v-power 4435 plugs.
They came out of the box at 0.40 so I installed them with that gap.
Truck is 4x2.

The distributor rotor I installed is the exact same as the one that came off but in a effort to try , and figure out what is causing this I reinstalled the old rotor ,but it still does the same thing. I also pulled the plugs back out ,and bumped the gap to 0.44 cause that is what Advance Autos computer called for.

Tomorrow I will get it hot again ,and check the resistance on the calipers.
I did just take a drive less than a mile ,and of course it felt great.

 

[Towncivilian]

OK, you are not affected by the transmission TSB because you have a 4x2. 0.044 is a little high (I mentioned the FSM's spec in my first reply) but I doubt it'll be an issue.

Good luck finding the problem.

 

[Anthony]

Yeah I saw your response about the gap.
I initially installed them at 0.40.

I just made the adjustment to see if it would make any difference.

 

[Anthony]

Well I swapped the cap today.
No change. I took it for a drive and then jacked it up to check to see if the front calipers were locking up.

There was no problem there.
The only thing I have not swapped yet is the plugs.

Still has great power when cold.
Ignition control module maybe?

Maybe the heat is affecting the coil?

 

[Towncivilian]

Perhaps the coolant temperature sensor, O2 sensor(s), or ignition coils are faulty, since it only happens once it warms up (i.e. when the sensors are used)?

 

[Anthony]

Well I installed a new coolant temp sensor this morning, No change.
I also did a O2 sensor after that.

No change. I do have another vehicle so I may have to park this thing for awhile!

 

[berniedd]

My friend's Toyota also recently had power loss. Other than that, car was fine. No starting issues, no bad gas mileage, no exhaust smoke. Diagnosis was bad fuel injectors. He had 'em changed and car was fine again.

 

[Chris B.]

It is a Nissan.....they never had power to begin with. I kid, I kid....lol

 

[Merkava_4]

Originally Posted By: Anthony

A couple of days ago I installed new NGK V-power plugs, NGK wires, a new cap ,and rotor ,and a fuel filter.


Did you have NGK V-power plugs in there before ?

 

[Anthony]

Originally Posted By: Merkava_4
Originally Posted By: Anthony

A couple of days ago I installed new NGK V-power plugs, NGK wires, a new cap ,and rotor ,and a fuel filter.


Did you have NGK V-power plugs in there before ?


Yes this is the 3rd set I have put in this truck.
I had a 97 with the same engine that came from the factory with them. This engine is not picky about plugs at all.

I had run Autolite platinums at one point as well as Bosch Platinum+4s in the 97.

 

[CBR.worm]

MAF? TPS? something that got bumped while everything was apart?

Coolant temp sensor or wiring would be my first suspect.

How are your MPG?

 

[Towncivilian]

Originally Posted By: CBR.worm
MAF? TPS? something that got bumped while everything was apart?

Coolant temp sensor or wiring would be my first suspect.

How are your MPG?

The OP already replaced the coolant temperature sensor and an O2 sensor.

 

[Anthony]

Messed around with the truck a little bit today. Unplugged the MAF while it was running and you could tell it was running alot richer and would peak at around 2300rpm so I believe the MAF is fine.

Also put a vacuum pump on the EGR and pumped it up ,and it stumbled ,and almost stalled just like it should so the EGR flow is fine.
I guess the next step is to remove the cat ,and drive it around ,and see if it changes.

There is no valve on the fuel rail so Im not sure how to check the fuel pressure. Will most likely take it to the dealer for a diag if I dont get anywhere with it tomorrow.