Hi, My 92 EX Wagon sometimes sputters and misses during driving at lower rpm's and mid throttle. When it sputters and I push the gas pedal all the way down it takes off like a rocket. It is idleing fine. It runs well above 3000 rpm on the highway in 4th and 5th most of the time, it might sputter going up a hill as rpm's drop at speed. I just drove from FLA to Cali with this and made it, then replaced what I have done below. It only sputters sometimes, not all the time. It has 270,000 miles on it. I have replaced the Coil, Dizzy, plugs and wires.
I replaced the TPS and it still sputters... When I Unplug the TPS it runs fine (not as responsive, but runs well). can I run it without the TPS, for how long? and where does the TPS send it's signals to that might be the issue ?
Any ideas ?
chuck d.

 

Does your Check Engine Light come on at all?

At this point, it could be a few issues. First thing I would look at would be your 02 sensor. They make a huge difference in how these cars run, and does cause issues like you describe. However, a bad 02 sensor will generally set off the CEL.

It really could be anything right now. Dirty injectors, dirty fuel filter, sticky throttle body, bad TPS.

Biggest thing to help right now is knowing if you're getting a CEL or not.

 

hi, Yes the Check Engine Light comes on after driving for a while, anywhere fron 2 to 10+ minutes.
The fuel filter was replaced too.
the sputtering was only happening sometimes, not consistantly, it may be happening more often recently. It started 3000+ miles ago, and 3 weeks ago.
It is usually in 2nd and 3rd gear at lower rpm's, but a few times in 1st, 4th and 5th gear too. the EGR was tested as working...
confounded. chuck d. thanks...

 

Read the CEL, and it sounds to me like it'll be your 02 sensor.

My car did the exact same thing.

 

Clogged EGR ports can cause your engine to sputter at certain RPM as well.

 

Hi, I've been running it for 100+ miles and a day and half with the TPS unplugged and No sputtering or missing at all. (yet). It is a MT 5spd wagon. clogged EGR ports don't look easy to clean...

chuck d.

 

ok, now halfway between LA and Vegas it started sputtering and missing with the TPS (throttle position sensor) unplugged. the cap had white corrosion on the contacts, too mch for 4 days of driving And the rotor had dark chocolate colored soot like stuff on it's metal contact area.

I was getting a 4-3 code... 4 long 3 short. a guide I found said 4-2 thru 4-? was all TPS...

thanks for looking chuck d.

 

Driving with the TPS unplugged is going to throw the car into limp mode. The check engine light is going to come on and it's going to throw a tps out of range code.

If it only sputters when the car is warmed up, and not when the car is running from a cold start, it's the egr system that is the cause since egr only works when the car is hot.

 

43 also points to fuel issues, test the O2.....and like everyone else, you didn't have a code 7 as well?

 

o2 Sensor can bite the dust on OBD1 and not cause a CEL. Mine did. The key to diagnosing is thinking about what the hesitation is like. Insufficient EGR Flow doesn't cause the kind of "barely drivable" bogdown that a bad 02 Sensor sending bad information to the computer can.

"At speed" as OP described it will present as almost like an engine knock as the speedometer drops despite the driver staying on the gas pedal. At lower speed the car bucks and stumbles as the ignition system tries to make the engine propel the 3,000 pound car while burning the bad mix that the o2 is causing the fuel and IACV systems to make.

 

bad egr valve/map sensor.

if you disconect the o2 sensor the car will run fine too.

the timing of the egr valve is not as it should be when it gets the signal to open up.

this problem is not very common with these cars but it happens to unfortunate some like me lol.

 

i had this same problem and it was a bad map sensor and 02 sensor +dirty egr ports. you can unplug the vacuum hose from the egr to see if it stops. go to a junkyard and grab some map sensors. make sure all those vacuum hoses are good.

before replacing the o2 sensor remove it and see if the end looks burnt. if it is it will need replacing. stick with denso products. bosch<denso

 

I'm having the same problem with my '93 EX (automatic). Where exactly is the o2 sensor located?

 

In the pipe after the manifold but before the Catalytic Converter.

 

Ok found the o2 sensor but I have another problem. I decided I would clean the egr ports and replace the gasket today. The first nut came off no problem but the 2nd nut was stuck. Sprayed wd40 and waited awhile, still would not come off and is now starting to strip. I cannot get this thing off. Anyone got any tips? The edges of the nut are starting to get rounded.

 

You need a wobble socket in whatever mm those nuts are. That will let you snug onto it and then twist from and odd angle that will kind of apply torque and a grip that won't slip at the same time. When I did mine, I bought the wobble (flexible) socket from Sears. I think the EGR is 10mm, possibly 12mm. Anyway, I went ahead and bought 8,10,12 and 14 at the same time. All have come in handy.

 

Thanks again. It is 12mm.

 

Went to the self-service salvage yard yesterday and pulled an OEM O2 sensor from a '91 EX. Cleaned it off with brake cleaner and put in on today...worked. The CEL hasn't come on again, but I might not have driven it long enough.

 

What the hell is a CEL?? You mean the MIL?

 

CEL = Check Engine Light