My mom has a 2003 TL and when she is driving it starts to shake randomly but more like a throttle/fuel/ignition sputter issue. So I plugged in my computer to the the car and I got 2 codes 31-02 PFINH signal malfunction and 34-02 throttle position reference voltage malfunction. I'm not sure what it is I have to do to fix the car but any advice or the exact information on how to fix this issue would be greatly appreciated. Thanks

 

those are not acura codes,,plus codes are clues not diagnosis
but guessing based on description= it has a bad coil
should give multi cyl misfire codes with that problem
any parts store (except in Ca) will pull codes for free
report back with those

it its misfire code buy 1 new coil and test on suspected cylinders
you can unplug coils 1 at a time and ck for rpm drop- no drop= bad coil

after new coil install or swapping them around to test: you MUST reset the ECU!!
simply pull CLOCK fuse on passenger end of dash for a minute
start car and drive-retest codes

very rare to have the probs you say codes mean
I would suspect battery condition and ground cables for those results
false codes but real problem somewhere else

 

there are several small braided wire grounds from frame to engine parts
plus batt neg cable

those are wearing out- rusting-breaking etc recently
they are there to help provide stable voltage to sensors,,as one code notes is not happening

 

If your CEL is on and the car is driveable, take it to a local autoparts store and have the codes read. My guess is that your mom's TL may have a case of bad gas. While at the store, have them load test the electrical charging system, ie: battery & alternator.

Chances are that either a coil or injector may be causing the faults. Try a good fuel system cleaner. Ensure that all vacuum and electrical connections are tight.

 

Always use 93 octane. I'm going to try fuel injector cleaner followed by coil test and go from there. Also going to check battery but I know it's not that it's had the problem for years we just ignored it because it was very random that it happened but not it's frequent and alot more aggresive. I do think it could be a sensor.

 

No CEL by the way.

 

Hey Tony, usually most faulty sensors will throw a CEL, but not always. Things like clogged EGR passageways and TB intake can cause poor running. It's a good idea to try a quality brand of concentrated "total fuel system" cleaner with about a quarter full tank of gas. The better "93" premium gas does have additives and is definitely a wise choice. Some like to use "Seafoam".

I've experienced a bad coil, ran like it was missing a cylinder ! But, then again usually you'll get a CEL. Maybe you have a dead spark plug or a vac leak ? How many miles....and when was the last tune-up ?

Is the shaking not showing any specific pattern, such as when engine is cold or at low rpm's at idle or coming to a stop ? A bad coil usually is like .....all the time !

 

seafoam or bg44 are top quality crud removers

seafoam run 1 can in just under half tank of gas, thats 2 oz per gal, more wont make it work better
do that twice for full system cleaning

longer drives,,30+ minutes help--it likes heat and that will clean the injectors really well

did we already cover egr system cleaning inside the intake manifold?

 

The shaking is during normal driving not really during stopping or at idle. The car has about 100k now and I don't remember when the las tune up was done. I'm going to do the file cleaner this week and the coil test also and go from there.

 

100= it needs new spark plugs
rare to find them replaced on a used car as plugs not called for until the 105
but we known they are toast after 70~

use the correct ngk only,,many here like the iridiium or iridium ix
about 8 bucks each are the correct ones

dont let the parts counter kid sell you some `2 buck chucks` --they dont work in our high energy ignition!!!!

clean TB air plate, throttle return spring assembly
do seafoam thru TB- works instantly on pistons and intake valves from there
and a can in half tank of fuel

 

Okay so I tried the seafoam 2 bottles and nothing checked spark pkugs and there good thinking of replacing fuel pump?

 

Have the fuel pressure checked first. Could possibly be a restriction in the fuel system, perhaps the fuel regulator ?

Were the spark plugs NGK,s? If not, replace them !