Rough idle

NISSAN 240SX
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MBRUCE84
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1989 Nissan 240SX, Rough idle. Car runs just fine when I'm at speed, but at all times when idling it's very rough. I have replaced the intank fuel pump, fuel filter, air filter, spark plugs, spark plug wires, and the oxygen sensor yet it continues to idle rough. When I got the car about a year ago it ran just fine and as far as I know the timing has not changed(or at least I don't know why it would have) I'm the only one to work on it. Please help fix my baby!
Mar 6, 2006 at 6:08 AM
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FISHERMAN
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Did you serviced the fuel injectors?
its that model 4 cylinders 8 spark plugs?
Mar 6, 2006 at 7:04 AM
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MBRUCE84
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No I have not serviced the fuel injectors. It's only 4 Cylinders and 4 spark plugs 2.4L. Is there any way to service the fuel injectors without taking it to a shop or opening up the engine? I am kind of weary about messing with the timing belt. I did a head gasket job twice on my old Pontiac Sunbird and replaced the head gasket correctly both times, but had to take it to a shop because I couldn't get the timing right even with my inductive timing light.
Mar 6, 2006 at 9:11 AM
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FISHERMAN
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im afraid the professional way to service the fuel injectors is to use the especific machine (its connected to a port on the injector manifold and pumps a strong cleaner fluid meanwille the engine its running) well you can start with a good injector cleaner on your next tank of gas, also check the intake manifold for buid-up slug and be sure you dont have any vacuum leak somewhere.

hope this solve your problem.
Mar 6, 2006 at 1:44 PM
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MBRUCE84
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I have in fact tried a fuel injector cleaner quite often actually and this has done nothing. I will take your advice and see what I can do. Any advice on a [b:491a554051]decent[/b:491a554051] fuel injector cleaner?
Mar 7, 2006 at 1:07 AM
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SENTRAMAN
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Did u try replacing rotor and distributor?
Mar 7, 2006 at 9:03 AM
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MBRUCE84
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I did think about it, but when I checked the timing with my inductive timing light the timing looked fine. I also opened up the distrubutor and it didn't look too worn. I went out and checked out the fuel injectors today and unknown to me they're not inside the engine so they look pretty easy to get to and off. If anyone knows how to clean the fuel injectors i.e. water, specific cleaner, etc. [b:45b5bb384b]PLEASE[/b:45b5bb384b] let me know.
Mar 7, 2006 at 1:08 PM
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Suggested Repair

Have the fuel injectors professionally cleaned with a dedicated machine. Also inspect the intake manifold for sludge buildup and check for vacuum leaks. A fuel-tank injector cleaner was already tried and did not help.

Conversation Summary

The owner of a 1989 Nissan 240SX reports a rough idle while the car runs normally at speed. The in-tank fuel pump, fuel filter, air filter, spark plugs, plug wires, and oxygen sensor were already replaced, and timing appeared correct. An expert suggested professional injector service, a fuel additive, an intake-manifold sludge check, and a vacuum-leak inspection. The owner said additive cleaner had not helped and asked how to clean the accessible injectors; a distributor and rotor suggestion was considered, but the distributor did not look worn.

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