I'm trying to fix a "Cylinder 1 misfiring" problem - code 0608 - on a '97 Altima. I've replaced spark plugs, plug wires, distributor cap, rotor, but still have the problem. The car runs okay until it warms up, and then it loses power a bit and the Engine Check Light comes on. I've checked the injectors using the screwdriver test (listening for clicks) and they seem fine. Any suggestions?
Thank you in advance.
Since you took care of the ignition side then it points to something with the #1 injector. Could still be a bad injector. Also check the injector's bottom o-ring and rubber insulator that the injector sits on. One often used tip is to swap the #1 injector with another side to see if the problem moves.
Thanks for your inputs. Yes, I pulled the connector and the engine changed to a different sound. But I also noticed that the clicking sound I heard on injector #1 when I put the connector back on was a little different from the rest of the injectors - like slower (?).
How complicated is replacing the fuel injectors? Any special precautions or tips? I've been told that it's a fairly simple job -disconnect battery, pull fuse, run engine dry, replace injector. Can I just pull an injector individually or do I go by the book and pull the whole fuel rail? Can I use aftermarket parts from Autozone?
Strange thing is injector 1 (the 'bad' injector) measured 11.3 ohms (spec is 11-14). But this resistance is the resistance of the coil, right? So I suspect it is physically bad somehow - like clogged - although it may be electrically good. That's my thinking anyway. Yes, I plan to change all injectors - the vehicle has over 200K mi - but with money being tight right now, I'm going to start with injector 1 first and see how that goes. I sure hope it works!
Okay, I replaced the "bad" injector #1 with a new one from Autozone. The old one did take some persuasion to remove, but I did it.
The car started and ran fine - no code. Until after a couple of miles, then all of the sudden the Engine Check light came on again. Same code "Cylinder 1 Misfiring".
Injector clicks fine.
So I have brand new plug, wire, distributor cap, rotor, injector.
I checked the plug well. No oil.
Thanks again for any insight!
Some other possibilities I can think of that would cause a single-cylinder to misfire are,
1. A compression issues with #1 - need to do a leakdown or compression test to confirm.
2. Internal coolant leak. (Someone, I believe niceguy, once had a small coolant leak that was causing a single cylinder to misfire.)
3. Intake air leak to the #1 intake runner.
4. Clogged EGR ports in the intake runners that is sending the majority of the exhaust flow down #1. This in turn will upset the A/F in #1 and cause a misfire.
jserrano: Thanks for sharing your expertise. I took the car to a garage, and the mechanic said either valve or intake gasket. He hasn't looked at the car yet, but I'm dreading the estimate... Any ideas as to a "reasonable" ballpark cost for either scenario?
Okay. The mechanic said he couldn't find anything wrong with the ignition, fuel injection, valve compression. No vacuum or intake leaks either. He's thinking the head gasket went bad causing a coolant leak into cylinder #1. Unfortunately he cannot test for this yet, because he also discovered a radiator leak which has to be fixed first. So he quote me $400 for a new radiator, and $1800 for a new head gasket (assuming it's the head gasket that's causing the misfire). Can I just fix the radiator first and delay the head gasket job a while?
Thanks again for any advice.
After the radiator leak repair he should be able to pressurize the cooling system to see if it drops in pressure over a relatively short time. Don't do the head gasket unless its 100% confirmation that it is causing the problem.
Since I don't have a lot of money to put in a 13 y/o car with over 200K mi, I took the car back from the shop (after paying them for the diagnostics) and I'm going to work on it in my spare time:
1. Right now I'm thinking about fixing the radiator first, because a cooling leak is the most urgent item. A radiator shop told me they can replace the plastic tank for $170 (instead of replacing the whole radiator). Is this just a band-aid? Or shoud I order a new radiator and replace it myself? If I do it myself, what's the best way to clamp the A/T cooler hoses?
2. Does the '97 Altima have an ignition coil for each cylinder? If so, is it possible that my #1 misfire is caused by an ignition coil? Where is this coil located?
3. I discovered a slight oil leak in plug well #2, so the valve cover gasket is leaking. There was not a puddle in the well, just enough to wet the plug. Now plug #1 is bone dry. Is it possible for #1 misfire to be caused by this oil leak in #2?
Update: I haven't fixed the radiator yet, but I've replaced the valve cover gasket (I did it myself). The oil leak seems to be gone as far as I can tell after several miles of testing. But the bad news is the check engine light came on again - same old thing: cylinder #1 misfire.
I've read that a head gasket is typically two adjacent cylinders misfiring, which makes me a little skeptical as to the mechanic's suggestion to change the head gasket.
Could my problem be related to the distributor - can a distributor oil leak cause a single cylinder misfiring?
Thanks again for any ideas on this.
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