engine rough when warm
05-11-2004, 08:11 PM
#1
Guest
Posts: n/a
engine rough when warm
Sorry if this has been asked before, Im new here and have scaned thru forums but this problem is a little bit different.
Most every one here says there problem is with cold engine problems, rough running. Mine is when engine warms up.
1990 2+2 N/A 5 speed - POP filter
Did ECU diag and came up with temp sensor, replaced it and fixed my rough Idle problem.
After warming up (driving) I get a engine miss when cruising at constant speed. This has been a constant problem even with bad temp sensor.
When shifting I get a slight hesitation when accelerating and the very rare backfire but then picks up and runs strong.
When braking, Idle drops low and almost stalls then returns to normal.
I replaced spark plugs, Temp sensor, Have new PCV's havent installed yet ( looks like a pain to do).
Haven't done a ECU reset yet.
If it were a leaking injector I should still notice it running rough when cold, same if a bad coil pack.
I've checked for vacume leaks but none I can find.
Everything I've read at www.zhome.com points to the PCV's or EGR, niether one I'm looking forward to doing.
Any suggestions or if anyone has had this problem and knows of a fix would be greatly appreciated.
If there is a forum that talks about this please post link.
Most every one here says there problem is with cold engine problems, rough running. Mine is when engine warms up.
1990 2+2 N/A 5 speed - POP filter
Did ECU diag and came up with temp sensor, replaced it and fixed my rough Idle problem.
After warming up (driving) I get a engine miss when cruising at constant speed. This has been a constant problem even with bad temp sensor.
When shifting I get a slight hesitation when accelerating and the very rare backfire but then picks up and runs strong.
When braking, Idle drops low and almost stalls then returns to normal.
I replaced spark plugs, Temp sensor, Have new PCV's havent installed yet ( looks like a pain to do).
Haven't done a ECU reset yet.
If it were a leaking injector I should still notice it running rough when cold, same if a bad coil pack.
I've checked for vacume leaks but none I can find.
Everything I've read at www.zhome.com points to the PCV's or EGR, niether one I'm looking forward to doing.
Any suggestions or if anyone has had this problem and knows of a fix would be greatly appreciated.
If there is a forum that talks about this please post link.
05-11-2004, 09:29 PM
#2
Registered User
Join Date: Mar 2004
Location: Windy City Area
Posts: 55
Well you've come to the right forum, Its a very difficult problem. When you ran the ECU Diagonostic did it come up with anything else cause the ECU should sense that. It does sound like a fuel problem, cause something is not flowing smoothly from you fuel cause your hesitation definatly sounds like fuel related. Check your fuel lines, filter, everything, etc. Whatever it is I can garantee it's not gonna be a fun job. I've never run into any problems like this but the 90-91's have various small little problems i would recommend checking out Rizz's signature and going to the nissan online service manual. But run an ECU check again and see what readings you get an go from there.
05-13-2004, 11:17 PM
#3
Administrative Brown Guy
Join Date: Jun 2003
Location: Ontario, Canada
Posts: 5,406
Dumb question, but I gotta ask.........
You are using 93 octane premium fuel right???
Sorry, I had to ask.
Assuming that's ok. I'd double check the connections to the Coil Packs. Measure them with a multimeter, they should all read about the same resistance. Same with the injectors. Check the online service manual for what values that you should be getting.
Another question for you.....What spark plugs did you use? I hope they're the factory equivalent NGK's.
You are using 93 octane premium fuel right???
Sorry, I had to ask.
Assuming that's ok. I'd double check the connections to the Coil Packs. Measure them with a multimeter, they should all read about the same resistance. Same with the injectors. Check the online service manual for what values that you should be getting.
Another question for you.....What spark plugs did you use? I hope they're the factory equivalent NGK's.
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