P0174 & p0300

[rthomsonTR6]

I bought my X (2000 6 cyl 5spd) about a month ago and on the drive home the service light came on. it was P0300 random misfire so i did cap and rotor on top of new plugs and wires installed by the PO. I've checked the distributor for shaft play, there's none. the misfire is quite insignificant but the most noticeable at idle. Another symtom im exspericing is a pretty bad hesitation. It comes and goes but under normal acceleration it will hesitate for about 3-4 seconds approx 300 revs then start pullinng normally. it seems to be worse when the engine is cold but will do it when its warm as well. i think the P0174 (Bank 2 system lean) is the reason for this. Ive checked the resistance in the bank 2 O2 sensor and it meets spec. ive changed fuel filter and used sea foam a couple weeks ago and that seemed to really improve the problem but not eliminate it. any thoughts? has anyone had similar issues?

 

[Prime]

How many miles?

 

[rthomsonTR6]

138K but the motor was replaced with one that had 90K on it, according to the PO... it was replaced about 10K ago

 

[Prime]

OK, has any of the exhaust been replaced? Reason being, the hesitation sounds like a clogged catalytic converter. Mine didn't make it past 110k. Would also explain O2 errors.

As far as the random misfire, there's only a few things that would cause it. Plug, wire, cap, rotor, or distributor. These trucks don't have a traditional ignition coil like most other engines.

 

[TheFauxFox]

OK, has any of the exhaust been replaced? Reason being, the hesitation sounds like a clogged catalytic converter. Mine didn't make it past 110k. Would also explain O2 errors.

As far as the random misfire, there's only a few things that would cause it. Plug, wire, cap, rotor, or distributor. These trucks don't have a traditional ignition coil like most other engines.

Just curious if back pressure could cause a misfire code. Its not unheard of to have catalytic converter innards suck back into an engine. I don't think the OP is at that point, but I was wondering if the two are connected.

 

[Intender]

Even without play in the distributor shaft it can still be bad. When mine went bad it didnt have any noticable play but when i pulled it apart it was full of metal shavings.

 

[Prime]

Just curious if back pressure could cause a misfire code. Its not unheard of to have catalytic converter innards suck back into an engine. I don't think the OP is at that point, but I was wondering if the two are connected.

Yes.... Kinda.... . But it won't throw a code. The code is thrown when the circuit is not complete to the spark plug. If the back pressure is so high that it's leaving to much crap in the cylinder and not burning, it's technically a misfire, but at that point there is nowhere for the exhaust to go because the engine is clogged. So it'll just die.... Or run so poorly it's not even funny.

 

[rthomsonTR6]

just the muffler has been replaced, not the cats. I live in eastern MD where there is no emission testing so i may just eliminate the cats and see if that helps. af far as the distributor goes looks like ill have to pull it apart to check for wear. @ prime i also have a 1973 Triumph tr6 so im used to non-coil pack ignition systems. Thanks for the insight.

 

[rthomsonTR6]

Well after pricing cats and not liking that number i looked into what else it could be and i was under the hood when i noticed that 2 of the 4 plugs for the O2 sensors weren't clipped into their little mounting tab and when i tried to put them on i couldent bc the wires were too short... then i got looking and noticed that the front left and the rear right o2 sensors were grouped together and the other two sensors were grouped togeather... The motor was replaced with one with 90k about 5k mi ago according to the PO. turns out whoever did the job got the plugs mixed up and thats what has been throwing the engine off. its nice when its something that doesnt cost anything but it sure was annoying. glad i didnt order new cats. The other thing was i was looking at the FSM and it showed the US spec with one cat, right off the manifold and the California spec with and extra cat further back on both sides. i have the extra cat but i live on the about 40 mins from the atlantic in maryland so at some point it made the trip across the country.

 

[Prime]

So codes resolved?

Mine was originally from North Carolina. And I have the 4 cats as well. I think at some point they just did that across the board. I, however, do not have the California spec EGR system.

 

[robcarync]

2000 had Federal spec with 2 total cats and CA spec with 4 total cats. Starting in 2001 they realized it was easier to just put 4 cats on all of them so they didn't have to keep track,.

 

[rthomsonTR6]

Yes, it seems like my codes are resolved. ive put a couple hundred miles on it and it seems to have no issues. my x was manufactured in may of '99 so it is a pretty early one so it would have been well before they started putting all 4 on. im going to look up the cali spec egr and see if thats what i have or if mine is like primes

 

[Prime]

If you have the EGR system, you'll have a pipe coming from the passenger side exhaust manifold to the throttle body.

 

[rthomsonTR6]

Is the only EGR on the cali spec or is there a variation in the egr system that is diffrent in cali. I do have a EGR system