# Bouncing RPM's



## jpcode (Nov 28, 2004)

I have two nissan altimas a 94 gxe and a 95 both automatic. The 94 has 260k miles and runs like a dream (first and only owner), the 95 has 185k miles and has had a few problems (not first owner, won't do that again). At 160k the 95's radiator split-since replaced the plastic with metal, and it blew a head gasget. I had it rebuilt and the only real difference I felt afterwards was that the engine was not near as quite as it had been before, and that it did not respond as quickly as the 94.
Now the 95. starts fine, runs for say seven minute just fine, as it warms though the idle rpm starts to eratically bounce between 480 and 1000. The engine seems to cough, is the best way I can discribe it every three to four seconds. I have experimented with tightening the acceralating cable, and once I get the rpms above 1100 they stop bouncing. I have chaged the roter and cap, plugs and plug wires, fuel filter(the one in the engine bay- not gas tank) I plane to change the pcv valve and egr vlave because I have read here that that is supposed to do the trick. I hate to do things I don't understand. What do these two little valves do?

Will it hurt my car if I wait till christmas break to change these parts?

Also I have located the pcv vlave and it looks near impossible to get to, what is the easiest thing to remove to get to it? And please don't say power stearing pump.

Do the fuel additives that claim to clean the injectors really work? Could that be my problem?


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## SPEEDO (Jun 9, 2003)

a word of caution... when it comes to cap/rotor etc.... use the factory stuff, for some reason alot of Nissans do not like the aftermarket stuff and they will run like crap!


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## mzanubis (Feb 19, 2003)

hes right, the like they're own parts when it come to the electronics

i don't think it'll hurt anything if you wait

i wouldn't trust my car to anything but Seafoam, go and buy a can, see if it helps


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## KA24Tech (Feb 2, 2004)

I would check the Mass Air Flow Meter by unplugging it while it is running. If the idle evens out then the meter is probably bad. If no change then try to adjust the Throttle Position Sensor to the correct .5v. Surging can also be associated with the Idle Air Control Valve or as you had stated the EGR. try the other two things first and then we'll address those other parts.

Troy


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## mick (Dec 30, 2004)

*Adjustments*



KA24Tech said:


> I would check the Mass Air Flow Meter by unplugging it while it is running. If the idle evens out then the meter is probably bad. If no change then try to adjust the Throttle Position Sensor to the correct .5v. Surging can also be associated with the Idle Air Control Valve or as you had stated the EGR. try the other two things first and then we'll address those other parts.
> 
> Troy


Do you unplug the 3 wire connector on the MAF to check it?
TPS--how do you adjust to 1/2 volt?
Will my car run if I remove the EGR?


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