enzo

I have a 90 SE, 5 spd.

I am having a problem with the engine loosing power in a specific
circumstance.

Start the car, drive a couple of miles, then take it on the highway.
Within about 4 or 5 minutes, I start to loose power, and the engine
bucks a bit. Sometimes it corrects itself, sometimes I have to
pull off the highway and this seems to correct it.

Never noticed it happening if I am running at street speeds (less
than 40 mph).

This doesn't always happen - I drove it about 300 miles on
a trip this summer, and it happened on the 280th mile.

I have changed the fuel filter.

Any ideas?

Mr. Nismo

iTrader: (36)

When was the last time you did a tune up?? Have you changed the timing belt?? How long ago did you replace the o2 sensor?? It could be a # of problems..........

MadMaxBrent

Perhaps it is one of the emission controls suchs as PCV or EGR valve. They are suppose to operate under certain conditions only. What does the car idle like? Any funny smells?

B.

enzo

Thanks for the suggestions,

I know it can be many things, that's what scares me.

Timing belt was done at 100,000 kilometres (63,000 miles) as recommended - I'm up to 160,000 kilometres now.

Just had a tune up and electricals done - distributor, ignition
coil, ignition wires etc.

It has happened 2 days in a row now - this morning coming to work,
I purposely stayed off the expressway and watched the engine
temperature gauge - almost as soon as the needle got to the
normal warmed up level, it started to buck me like a bronco, again
coming and going as in the past.

So I am guessing this has to be a valve or sensor that is
malfunctioning when the engine comes up to temperature.

I was hoping someone may have had the same symptoms and could
save me some pain.

Keep the suggestions coming.

brubenstein

If it's a function of heat (engine coming up to full operating temp, and then running poor), it probably the 02 sensor (particularly if it's never been changed). If it's a function of driving on the highway and then losing power, it could be a fuel problem: fuel filter or blocked screen on the fuel pump.

enzo

I can try changing the sensor as I have never changed it, but that seems like a long shot - I thought if the O2 sensor fails, the result
is too rich a mixture - can the O2 sensor cause the fuel flow
to be cut off?

I've also been following up on coolant temp sensor - it sounds
like the signal from that regulates about 100 things through the
ECU - I'll give that a shot as well.

enzo

This morning I drove to work, expecting the bronco to start bucking
again. I closely watched the temperature gauge and braised myself
when it got to mid range. But nothing happened. Ran fine all the
way to work.

Today the outside temperature is about 3 or 4 degrees warmer than
the last 2 days (when the problem showed up).

Only other difference I can think of is that I did not have
the heater this on morning.

Is there any relationship between the heating system and the
engine computer - I know, it's a long shot.

Brian_TII

What kind of parts were used? I found that I had problems with the engine missing when I used the standard "Autozone" distributor, wires, etc...

Good luck,

Brian Murray
87 RX-7 Turbo II (w/mods)
89 Maxima GXE (daily)

enzo

Parts were all off the shelf aftermarket jobs. I'm pretty sure this
isn't the issue though as the behaviour hasn't changed since
I did the tune up.

For the last couple of years my Heating System has been goofy as
well. Sometimes it blows cold air when it should be putting
out heat (in winter months), so I think the auto control of the
vents is screwy.

I was reading the Service Manual last night and found that the
ECU feeds the climate computer with the engine temperature signal.

The common sensor to these 2 systems is the engine temperature
sensor. I'm going to clean and or replace it this weekend and see what happens.

Keep those cards and letters coming in.

KITT

Maybe your injectors..... I found that my car needed replacement of all its injectors. I found that it corrected teh problem straight away. But it is very costly.

enzo

I did 2 injectors a couple of years ago - in that case they were
both dead - all the time.

This is very intermittent.

I replaced the temp sensor this morning - I'll report back on
any progress or lack of it.