slight miss at times

[tanker]

Lately I noticed a slight miss or skip in the engine, almost like it cut off then on again real quick. Not one cylinder, but like all 8?? :rolleyes: It is usally about 2000 rpm under light acceleration. Any ideas? :rolleyes:

[Turbine Doc]

Tom,
Mine had similar symptoms when I had a partially clogged fuel filter, that did not fully manifest itself until pulling a loaded trailer. I picked up a bad load of fuel somewhere; running empty I had the miss you describe but still had power, towing 5800 lb trailer up hills truck would hardly go over 30mph withou bucking felt like I was running out of fuel.

Replacing the fuel filt fixed that, I never thunk it until RATDOC suggested it as a possibility as I only had 5K on that filt. Might be a lift pump starting to head south as well.

[Kennedy]

Lift pump???

[Tough Guy]

Lift pump bad = runs like crap.

and or fuel filter, your results may vary...

Cheers

[markelectric]

I have noticed a "miss" on our suburban also. Ours seems to be a sharp miss. I had hoped it would go away through a injection pump swap but the miss remains. I am begining to think the torque converter is unlocking and locking giving that feel. Like tanker, it always seems to be under a lighter acceleration.

[piersbc]

My 95 is doing the same...I was wondering if the tranny needs a shift kit or something.

[JohnC]

Interesting! My '95 has the same symptoms: a miss or jerk under light loads. It's very infrequent, sometimes 2 or 3 times in a day and sometimes months with no problem. I had a trace from a Tech 2 that caught it once and there was evidence to suggest the TCC had released and re-engaged. No idea what could be causing it, though. It's infrequent enough that I quit persuing it.

[gmctd]

If the TCC\brake switch has been checked, try r&r'ing the connector plug at the trans - it's in a normally dirty environment, and winter temps and damp do not contribute to pristine electrical connections, GM 'weather-pack', or not.

[JohnC]

I wish I could remember for sure if this behavior predates my transmission R&R/overhaul. I'm sure it predates brake switch replacement.

[GARY PAGE]

I think it may be the torque converter coming out of lockup. I don

[tanker]

I must discount the fuel filter, I changed it this morning before a 200 mile trip, and it still does the skip. :rolleyes: The lift pump is less than one year old, but if it was bad, I would think I would lose power on a hill at full throttle, but I'm not. I'm also leaning towards the converter skipping a beat. My converter only has less than 30,000 miles on it since I replaced it. I'm going to look at the connections. Today it did it about 6-8 times, and my wife can feel it on her side, not driving. Oh! modern technology :eek: .

[rjwest]

I had a slightly rough running engine at 1500-1600
rpm , just ignored it. Than FSD Fail,
would not start, than start etc. Remoted FSD
alls well, still had miss. Than
had a bunch of " quit " restart ok. very intermittent. got worse, changed FSD
thought it was fixed. than same problem several months latter.

So, FSD's are easy to change , try another,
alls well again for awhile. untill the problem started again. when starting in morning
Temps 40-50 deg it would quit several
times than be ok all day. went on trip out west.
starting to have problem on start up , hot or cold, after 10-30 minutes, quit/restart
than ok.......Called Gomer. New Injector
pump. ALLS WELL for 20K miles. Starting to love my truck. Oh, Miss at 1500-1600 is gone and has more power........Only once did i get a code
through all of this ( inj pulse to short )..
And Chev was NO HELP AT ALL!

6.5 Diesels are Like a Girl I new in High School.
Really great when all's well, But what missery she could put you through when she wanted to be in a bad mood.

[stig]

Sounds like a GM built in feature of the 95 Sub. I have the exact same symptoms as tanker.

gmctd - Could you explain what the TCC/brake switch is to a novice (me)? How should I check it etc?

BTW - is this GM feature a potential big $ item and if it is so common is there a recall?

The clunk/skip/fishbite occurs usually on constant gentle acceleration, about 2000 rpms - highway cruising. It can really surprise you.


I'd like to eliminate this so I can worry about other GM engineering features.