Hi guys!!

Mother's day tomorrow!! For those of us lucky enough to still have our mothers, call her and tell her you love her!!

My 94 360 sat (again) for 3 months without being used. It started to hesitate under light throttle. CEL was on but it's been on since I cut the cat out (did not have time to do the non-fouler mod yet... I'm a procrastinator ) If I give it more pedal then it picks up, but in stop and go situations and light throttle to maintain speed, it runs rough.

So after a few days I did the key dance and got a new code, 41. Charging system something something.

Gauge is still at the same spot and truck started fine all along, even when I started it a -30C a few times when it was unused.... But I just read somewhere that the ECM is VERY sensible to voltage change and COULD cause the hesitation I'm wondering about.

So I come to the experts:

Can that very low ( imperceptible) voltage change cause an hesitation at light throttle?

Anybody experience this before?

Suggestions on what it could be?

Thanx y'all!!

 

Since yours is a 94, you don't want to do the non-fouler trick, as you only have one O2 sensor. PCM doesn't care about cat efficiency, and there are no codes for it on the OBDI systems.

PCM is whining about apparent battery voltage falling below 11.75 volts...... If the alt gauge isn't reflecting this problem, I would start looking at the connector on the PCM, and make sure things are clean and tight. Also check connections at the alternator.

 

Thanx HeyYou for the non fouler tip. Good thing I'm a "do it later" kinda guy eh? Lol


While on the subject, it also shot twice code 21, for the o2. Is that normal?

Come to think of it, this hesitation came right after i changed the water pump. I'm trying to look around to see if I pinched something but everything seems fine....

 

Check the grounds over by the power steering pump. Folks sometimes forget about those, and the PCM REALLY needs them to be good.

 

Ok Thanx HeyYou for the advice...

Disconnected all of the grounds at the water pump, cleaned them, put back together... still no difference. I guess my next step is to pull the plugs and see what's going on in there.

Also did the overdue zip tie thing on my throttle cable, it had a good 2in of loose at the pedal...

Think my plenum is blown again....so maybe the plugs got fouled by that...

Tried disconnecting the TPS, it seemed a little better but when I let go of the pedal it wants to die (normal I guess).

Other symptom I forgot to write, maybe it will help pinpoint the problem.... When I let go of the gas before stepping on the brakes, it sounds rough (like on light throttle) but when I come to a complete stop it surges a little and runs better, until I step on the gas again....

Other thing....

The TV cable adjustment... Everywhere I look they talk about and show a white retainer clip... I don't have that. Mine is different looking and black. Is it a thing on the 94 or did I just ''lose'' that part?? I remember on my Dad's 96 it had the white clip....

 

May just be a different color. It's a locking clip, so, it *should* be there.

Pull your plugs, see what they look like.

When you did your plenum, did you just replace the gasket?

 

Yup on the plenum... did not have friendly advice from the experts here, so just did the gasket....

 

Ooops. Yeah, have a look at that. See what ya got.

 

If you change the plenum gasket using the OE steel pan, grind the 1/4" unthreaded portion off of the pan bolts. They seem to be just a tad too long, preventing the pan from squeezing the gasket as much as it should after it's tightened down. Screw one of the stock bolts in place without pan or gasket and you'll see it bottom out and still leaving a gap between bolt head and manifold.

 

On my 96 on the side of the TV cable you just push in and it release the cable so it can be adjusted, no clip involed.

Dave