I replaced the fuel filter and no luck. Should I try injector cleaner and fill up with premium gas? Should I replace the fuel pump, air filter, plugs and wires? Ecu thingy? It is a 1988 nissan 6 cyl. Need help in bama. Ty, Jay
Fuel pump: Not until fuel pressure is tested.
Air filter: most likely yes, how many years/miles since last changed?
Spark plugs: most likely yes, years/miles since last changed?
Plug wires, as with the spark plugs.
Premium gas: NO, however your vehicle may not have been designed for gas with ethanol. If not, non-ethanol gas may be beneficial, but damage to some components is already done. Those components will need to be repaired/replaced.
Your truck should have an OBD 1, is the check engine light on? Are there any shops in your area that have a code reader for OBD 1?
Original catalytic converter? May be clogged.
Is your truck sufficiently rust free to do the above?
Are brakes, tires, and suspension components good?
2 Likes
Do you have a check engine light on? This is important. If it is on, then there is a procedure to get the code and it does not require a code reader. You will probably have to buy a Haynes manual for your truck to get the procedure because there was no standard procedure at the time.
If the check engine light (MIL) is not on and you don’t have a misfire under normal driving or idle conditions, the most likely culprit is the oxygen sensor (O2 sensor). You probably have one in each exhaust manifold but you could have just one located in the exhaust pipe after where each side merges to one pipe.
O2 sensors slow down with age so they don’t respond quick enough for sudden changes in throttle position. This causes the stumble. There is a way to check them but you need the repair manual and either an analog voltmeter or a newer digital voltmeter with a fast response time.
I would just replace the O2 sensor(s) but first I would make sure that the spark plugs and wires are all good. Old plugs can also cause a stumble when the A/F mix changes suddenly and they aren’t sparking so good.
Despite the “D”, I’m presuming your D21 uses a fuel injected 6 banger gasoline engine. If so, I’d start by replacing the engine air filter and the fuel filter. After that, spark plugs and wires, distributor cap & ignition rotor. No harm to try a dose of injector cleaner, but I doubt it will help. Unless engine is pinging, premium gas unlikely to help. If engine is pinging and misfiring on rapid accel or going uphill, check spark plug gap. It may have widened with use, now wider than the spec.
Could be something else, but for those problems usually the check engine light would be on w/some diagnostic codes. If your truck uses a carburetor, oh oh, that’s a likely culprit. Carbs of that era, very complicated gadgets, hard to diagnose.
If nothing else seems to work, and no check engine light, you may have a clogged cat. Ask your shop to measure cat backpressure, or if they could temporarily remove or bypass the cat as a test.
If you are going to replace your spark plugs and ignition wires (plug wires) then don’t forget about your distributor cap and rotor button (as George mentioned), for some reason they get ignored but can build up corrosion as well as wear out… Also check your ignition timing as well as for vacuum leaks…
Basically play catch up with ALL your maintenance… Might not be a bad idea to do a compression test with an older engine while replacing the spark plugs, since they are already out…
There are lots of things that can be wrong or a little off (as mentioned by everyone above), but make sure you have the basics covered also…
Very good idea, as stated above. Compression test while plugs are out, dry and wet.
If this is an automatic, is the transmission downshifting?
The D21 is the body style designation. These were commonly called “Hardbody”. Hardbody was a marketing term but was never the official name of the truck, i.e. there was no hardbody logo on it.
Most D21 trucks came with a three valve per cylinder 2.4L SOHC 4 cylinder.
2 Likes
They also came with a SOHC 12V 3.0L V6…
And the 2.4L was a SOHC 8V, with 2 spark plugs per cylinder…
The Hard Body’s and Tacoma’s of that time looked great with 15" custom wheels and even lowered…
I see references for both a fuel injection system and a carburetor on 1998 Nissan Hardbody truck. Hopefully OP will tell us which of those his truck uses, as it could be important in the diagnosis.
They had a throttle body, so maybe the reference was mistaken the T-body for a carburetor… According to rock auto, 1985 was the last year for the 2.4L truck carb…
OP stated it is a six cylinder.
48 hours since posted. Ladies and gentlemen, Elvis has left the building.
1 Like
The early ones were, then they went to the 12V 4 cylinder with one spark plug per cylinder. That engine did duty previously in the 240SX.
The OP reviewed the replies yesterday.
And most had nothing to do with their problem.
I wouldn’t come back either.
Tester