Rant and question about wifes daily driver

[40ford]

My wife's daily driver (2002 GMC Savana van, 5.7 liter V8, 62,730 miles bought new) started having a problem. Under load it would stutter, quiver, act like it was not getting fuel for a couple a seconds, service engine/check engine light would come on and then it would stop stuttering, light would go out and everything would be fine. It first did this about a month ago as we were going up Mount Eagle, not a good feeling, on our way to Murfreesboro, Tn to see our daughter, SIL and grandson. It has done it a couple of times since then. With my total knee replacement operations coming up Aug 5 my wife said find out what is wrong with her van. Took it to dealer yesterday for diagnosis. This is what it said - First fail 1328 miles ago, last fail 105 miles ago, 73 mph, 4 fails 162 passes. Most history misfires on cyls #3,4,5,6 & 7. Refer to #PIP0381 Bulletin on uphill/under load misfire due to TIGHT VALVE GUIDES. For this condition, reworking of cylinder heads/valve guides is recommended by manufacturer. Dealer said it would cost thousands of dollars to remove heads and send them to machine shop and get them fixed and reinstalled. They recommended adding a quart of Marvel Mystery Oil to crankcase and just keep driving it and that is what they did.
Tight valve guides??? All engines I have had valve guides wear and get loose not tight with age. VW bug did get tight if you did not adjust valves every 3000 miles. This makes me really want to go and buy another GM product after this. I have had Chevys, Buicks, Pontiacs, Olds, and GMCs, the Olds gave best service.
Question - I have seen where Ted talks about adding trany fluid to oil, on the Flathead Ford web pages people add MM Oil to every tank of gas to lube upper engine.
I would appreciate your thoughts, opinions, experiences, etc., on this. Thanks.
Ron A.

 

[Baby Huey]

Be real carefull adding stuff to your engine oil in cars with a CAT ....They are easily plugged up by soot and ash deposits from engine oil additives...... "BH"

 

[Ted Brown]

You have a great point, I never use any of that smog crap, build a (test) pipe to take it out, then back in for testing.. only... make it last forever that way... (the cat)... :rofl:

 

[railroad]

Read the thread on Motor Oil. I think an oil or additive with the old amounts, something like 12000 ppm of zddp, might help. The zddp will not necessarily clog your cats, but enough of it will reduce their ability to burn off the pollutants.
We all were running the old SL designation before we got to the now SM which
has about nil zddp and the cats are fine. The Marvel Mystery oil and trans fluid
are more detergent that lubing fluid. If you decide to add some zddp, buy something from one of the racing oil or cam companies. Don't buy the snake oil, Z max or Slick something. They are just money wasters. Personnally, I would put in a bottle of Comp Cams break in additive and not tell the dealer. They will try to use it as a loop hole on the quality of your engine.

good luck,

 

[Wild Mango]

I pulled a rebuilder 350 down for my sons bucket a few months ago and all the inlet valves were carboned up so bad they looked like black candy apples and stuck so bad i had to hammer them out. No guide seals, just an o ring on the stem and sheetmetal skirts on the retainers, colleagues tell me this is common OEM. (??) Inlet rocker tips worn bad by comparison with the exausts. Rest of the engine was good, so I can only assume it ended up as salvage because of the valve problem - she would have been a smoker.
Point is, sucks oil down the inlet guides, they get sticky.

 

[rooster57]

I am tring to see how a tight valve guide could cause an electrical misfire!!!!!! I could see how it could cause an O2 failure beacaue of it. That chugalug may be a map sensor but it almost sounds like a loose connection on of the harness connectors. I think i would get a second opinion. Some of the dealerships have cut back so far you may not be getting an experenced tech to evaluate your problem. I would NOT put anything in the motor till i found out for sure what the problem is.

 

[putz]

Was it setting any codes or just rich.

 

[fbn8248]

how many times have you experienced this, was there similar driving conditions uphill, temperature under load, towing,ect.

 

[jbisme]

My 1990 F-150 did something similar to that. It was a lose connection on the water temp sensor. Who knew something so minor like that could cause my engine to act so crazy.

 

[putz]

I had one do the same thing if the computer is reading wrong temp it will send wrong adjustments.

 

[Screaming Metal]

You have a great point, I never use any of that smog crap, build a (test) pipe to take it out, then back in for testing.. only... make it last forever that way... (the cat)... :rofl:

Putz and the guys are right.......let me add this though.

The cars now aren't designed for us to go jacking around with their systems.......I wouldn't want to suggest anything that my cause youto void your warranty. In this day and ago......these IGMO's are just looking for any excuse NOT to replace parts that they should.
Ted and Putz are straight shooters....listen to these guys.

Cars now days aren't cars....they're rolling computer systems. They don't have 'Mechanics' at the dealers anymore....they have specialists that work within they're systems.

On the race cars I work with.....the computer gives us all the info on all our systems......everyone said we couldn't go much faster than 220 mph in the 1/4. Essentially we're running the same cars as we were 10 or 12 years ago.....but because we have the computers recording everything.....we use them for timing, fuel management, etc.......just like a regular car....but more simplified (in my opinion). We need to take a little horsepower out of the engine....we can back down on the fuel a little.......thatway the driver doesn't have to backpedal as much. For a really close race.......we can turn the rev limiter up, that actually bearly breaks up the spark enough that the engine won't granade on us. But because of the computers.....we've broke the 300 mark.........The funny cars are running where the top fuelers we running 10 or 12 years ago!

Cars are technology anymore.....the trans on alot are even controlled by computers, as are the whole engine management part. When the blower needs to be stepped up.....I ACTUALLY change the pulley myself!......no computer.

If your vechicle is under warranty.....let them straighten it out....they created all that mess................

If a valve clearence is too tight and made so it won't oil correctly.....it'll try to gall up.....which in your case its trying to do!!!!!!!

 

[40ford]

Thanks guys for the replies and info. I have a friend who went to GM mechanics school in the mid 60's and is an excellent mechanic on non computerized cars. He is retired but has a shop behind his house to work on family and friends vehicles. I will get with him and see what we can come up with using this info.
Ron A.

 

[Screaming Metal]

Hey guys.....I drove a electric not too long ago........remember when you used to ride your bicycles when you were a kid.....and put some cards and some clothspens on the frame so they'd hit the spokes so you'd have that engine sound???????????????????????????????????????????????????????????

Guess what......they need to do that on those electric cars!

 

[RPM]

[quote name='Screamin' Metal']Hey guys.....I drove a electric not too long ago........remember when you used to ride your bicycles when you were a kid.....and put some cards and some clothspens on the frame so they'd hit the spokes so you'd have that engine sound???????????????????????????????????????????????????????????

Guess what......they need to do that on those electric cars![/quote]

My daughter has a Toyota Hybrid. You can not here that car at all. Going across the driveway at the shop it makes no sound at all.

 

[kris-kincaid]

The new cars won't react favorably to a test pipe replacing the cat. There is an oxygen sensor before and after the cat. They compare readings and will let the computer know if the cat is going bad. If you put in a test pipe, the computer will think the cat has completely failed and put the car in limp home mode. In limp home mode, the car has awful performance and only goes about 20mph, but It beats walking though!

It's funny, I was just reading a late 70's Car Craft and saw a JC Whitney ad for test pipes. Who knew it was the end of easy to work on cars? :welcome:

You have a great point, I never use any of that smog crap, build a (test) pipe to take it out, then back in for testing.. only... make it last forever that way... (the cat)... :wacky:

 

[Baby Huey]

Just wonderin, does this engine use spark plug wires ?????? How bout swapping in a new set and see if that helps at all.... These days plug wires are about the cheapest "fix", sure beats tearing the engine down....:sad: "BH"

 

[speedkills502]

I would go with Huey there my be a service massage that fits but that may not be your problem. Do any service work it may need Plugs Wires fuel and air filters it may be coil over plug and want have wires but it still has boots on the coils. That will cost alot less and it may fix your concern. The guide being tight could make it miss fire, by the valve not seating fast enough and bleeding off cyc. pressure. GOOD LUCK.