Thanks Jon & ditto!! What did the tranny shop do that they know the TC is ok? Did you replace the IAC when you cleaned the TB? Bands been adjusted? You say your getting a misfire on #7 does your CEL come on and what is the actual code that could be a big help to know..compression test? Oil look almost like coffee-ish in color? any smoke for tailpipe(s)? NOT that this is your problem, in fact it's not but did you do the cap & rotor too?

 

I read this morning " Low compression in one cylinder usually indicates a bad exhaust valve. Low compression in two adjacent cylinders typically means you have a bad head gasket. Low compression in all cylinders would tell you the rings and cylinders are worn and the engine needs to be overhauled" also (after the dry test)

Worn piston rings / cylinder walls: After running the first test squirt 2 oz. of oil into the cylinder and crank the rotate the crankshaft three more turns per cylinder. If the compression increases the piston rings are at fault.

Burned valves: After injecting the oil in the cylinder the compression reading stays the same then one or more of the valves or valve seats are bad or not seating correctly. Low compression in one cylinder typically indicates a bad valve. Exhaust valves tend to burn due to the hot gases passing through while an intake valve is cooled by the incoming fuel. A burned valve is usually an exhaust valve.

Faulty head gasket: A faulty or blown head gasket will leak compression between two adjacent cylinders. When the other cylinders are within specifications and two cylinders next to each other on the same bank are low suspect a faulty head gasket.

Camshaft timing: When all of the cylinders are low and inserting oil into the cylinder does not increase compression the camshaft timing is likely off. The timing belt or chain can slip on the sprockets resulting in the staggered and low compression results shown in the image. Before replacing the rings in this engine check the camshaft valve timing.

Hole in piston: A hole in the piston will result in no compression in the cylinder. Remove the PCV valve from its grommet. The blowby gases caused by this hole can be seen seeping through the PCV valve opening.

Carbon buildup: Carbon buildup on the top of a piston will increase compression readings and can be seen with a probe inserted into the cylinder.

Hear is some good reading on diagnosing misfires too...

http://www.autotap.com/techlibrary/d...g_misfires.asp

 

Carbon buildup: Carbon buildup on the top of a piston will increase compression readings and can be seen with a probe inserted into the cylinder.

=Can also heat up and cause a flash point (pre detention) before the compression stroke is complete. This can damage the engine.. it can also cause the motor to shimmer as well..



And to answer your questions.

Not sure what the tranny shop did.. they said it was fine; dad said it was fine.. Tested the TC per a TSB i found on internet.. Foot on break and for 5 seconds romp on the gas.. (Stall test) Reverse FULL throttle MAX RPM was 2K would not go any higher.

Forward... I think it was 2-3K when the breaks could not hold her.

Oil.. If your referring to Black coffee then yeah.. after a few miles the oil is a black color like normal; if you mean with coffee creamer then no..

IAC- Cleaned it really good; tried to replace once but the new part i bought didnt work so i took it back and put the old one back on.. Idle control seems to work ok.. other than just being part of the emissions system opening closing randomly to keep that precious Air/Fuel mix for emissions .

Smoke- No smoke; never.. She smells a little rich at start up but that's about it.. till the CAT gets light up then turns to typical smell a truck equipped with a CAT smells like.

Bands- NO never adjusted them.. pretty sure not the problem in our case though.. because the symptom is there even in park.. watch my antenna and its bouncing like its going down the high way.. Just you can really feel it when in gear its transferred to the whole truck.

Code.. Well I don't know the code.. the chick at Autozone had this rack that was out of this world and i forgot to get the Code from her; but it was just misfire number 7 CYL> same one as before (Year-Year and half ago)

Basically; the truck shakes.. like you expressed; but sometimes it really shakes like extra hard.. when it does it.. it seems to have more get up and go though too.. for some reason.. but anyways.. take my foot off the break completely.. and just let her shake her butt off it threw the code..

 

I was thinking the following things..

Cam Shaft Lobe being warn..
Valves
Cam Sprockets and chain.. (thinking they would really need to be loose or something but i would immagine it would cause some racket i could hear through the timing chain cover with the mech. thest.



Have you tried changing your engine mounts yet??

 

No, my thoughts behind that is I would see lift when I'm under the hood and crank the throttle by hand. Also the shutter is only at two specific times (off a roll from a dead stop and as soon as it hits 40mph). And with the misfire/code I know I'm dealing with ignition, air/fuel or compression. I now know I'm in the compression zone since all others have been ruled out and have completed the dry comp test (with low readings). I'm about to do the wet type. The OBD scanner should give a letter/numbers code (I forgot to get the code too, went to advanced) along with the 'misfire #7' I'd really try to find that out 1st as it 'could' really point you in the right direction. MY opinon as far as my truck goes if I really think something is broken and I have the $$ for the parts I think it's ok to replace. Being a 98' with over 266k the parts should only make her happy..and yeah coffee with cream

 

Does yours look like coffee with cream? LOL..

I'm not sure about the 40; OD kicks in at 45 on mine; and then I can feel an occasional what ill call a hickup.. very light quick and random.. like up hills or what not when at constant throttle and maybe a little pressure on the engine like going up a hill..

I'm hoping we can bounce things off each other untill one of us gets it fixed. Place I got it from supposedly did compression test on it and said it was fine but who knows.. LOL.. I need to get it done and see what my numbers are looking like.

 

I'm sensing a correlation here..bad plenum, #8 misfire, bad cat and now a valve issue! I warmed the truck a bit more this time before testing..And the test results are...
dry:
#8-130-135
#6-178-180
#4-178-170
#2-160-170
wet:
#8-130-135-130

 

but get that code
If you do your own work check out the links..(we can always walk u through if not)

http://shop.advanceautoparts.com/web...ression+tester


We'll get um fixed..it's all in the diagnosis and testing, the real problem is the headaches during the process...

 

SO you think you have a bad valve on your number 8? That makes seance for the plennum; but My cat is good; my old cat was good i only replaced because I wanted a so called "High flow cat"

And my plen.. is still intact currently. Tested that already.. no change there Yet** key word..

But i could have a bad valve.. Does your exhaust sound like it has a mild cam?

 

I'm not sure, it does sound different tho..I was wondering if the cat did damage to the muffler while it was going bad? But with those comp test results at least I know it's a valve issue. There are more tests to determine weather it's a intake or exhaust valve problem. Hey could be an exahaust valve that's making things sound different?