I guess all i can say is that i've gotten my use out of the ole girl @ 202,000 miles but now she's decided to "act" up a lot lately... and as it occurs i've been taking care of the issues... But now i have an issue that i cannot quite pinpoint whether it's to the engine or the transmission...

About 6 months ago i rebuilt the 4R70W (the seal on the forward clutch piston came apart and well it wouldn't go anywhere). everything has really acted fine up til about a month ago. When the check engine ligth would come on and go off. not long after i rebuilt the transmission i had a slight act up that has now returned... but since it went away before after a day i didn't think much of it since i couldn't diagnose at that itme...

Now... i have a slight miss at idle in gear, forward or reverse.. take it out of gear and all is fine, or well the miss is hard to detect. Acceleration through first and second gears is fine... shifts are firm and shift from 2nd to 3rd is fine and firm...(yes shift kit installed). shift to OD and it does the high rpm thing til the engine is warm then rpm is normal with converter in full lock-up. the converter is locked, you can see this upon decel.

I did have an excessive egr flow code and replaced the DPFE which corrected that issue. Other than the alternator brushes wearing through the armature and the A/C compressor clutch grenading i have NEVER had an issue with the motor... Tune up every 50K and it is time to do it again... clean fuel system internals at 95K... needs it again for sure...

now to the issue... in OD when you tip into the throttle to climb a hill...ever so slightly, not enough to make id downshift you get what feels like a transmission slip or shudder, it jerks the truck... if you downshift into 3rd it continues to do it slightly once in a while until you let out of the gas. the issue goes away in 3rd and doesn't continue but will do it in OD... it is worse sometimes than others... i noticed it not long after i rebuilt the tranny and then the symptom disappeard and then reappeared a month ago...

At ths time i have NO codes thrown... when the EGR code was present and the truck would do this and i let it just go haywire the CEL would begin to flash. then when i let out of the gas after a minute it'd just go back to solid... i have not checked the code for this yet... duh me... i just have not gotten to it... what exactly does a flashing CEL indicate...

So some of the possible issues i might be facing is the break down of a coil pack, a sticking EGR valve (but sucking on it makes it actuate fine), plugged ports (but i don't get a low flow fault). Torque Converter Clutch Solenoid or a TC that is takin a crap.

I honestly though that the DPFE was the prime culprit but i guess not... it was calling for full scale voltage at idle in gear cold... but it has not corrected this OD issue...

i don't want to pull a tranny apart if that is not the issue only to find out i needed to be workin on the motor... and i know i have some more diagnostic work ahead of me... but some help pinpointing an area is appreciated...

It seems to be a misfire situation BUT the OD bucking and what not gets me... as say the band would maybe be slipping and grabbing... i am pretty sure, like 99% that i put the thing back together and it shifts fine, etc... notghing smells burnt and it has an external cooler...

but anyway, nough of my endless rambling... hopefully someone can assist my thinking process with some experience...

Thanks eh

J

 

Change your plugs and wires.

 

yeah, sounds like a missfire.

Id also look at plugs and wires.

 

I had this same condition. Only happened when under a load like climbing a hill then back to normal elsewhere. Took it in and mech. finally got scope to show a slight misfire in the # 3 cylinder. This plug showed faint traces of moisture so he dried the boot and reinstalled. Everything was fine for about a month then it started again. Being busy ans with no time for repairs I pulled the boot and shot some WD-40 in and reinstalled. Sure enough ran fine for about a month. Did the WD-40 thing again and voila, another month which brings me to now. After doing a search on this site Ive found three possible causes for the moisture. 1. The heater hoses which run above the 3 and 4 plugs and enter the firewall( I hope I hope)2. Manifold leak 3. Head leak When my bussiness slows down or I run out of water displacement-40 Ill take it in. Good luck and let us know what you find.

 

Failed to mention mine is a 97 with the 4.6 and 163000 miles. The shudder seems just like the transmission. Bucks, jumps, and turns on a flashing CEL for just a bit then stops flashing and stays on for a few startup cycles then goes off.

 

I currently have the same problem with my 97 (5.4), but mine finally showed me a code of #4 cylinder misfire. So, the first thing I did was replaced the coilpack. This fixed the problem of missing (shaking, etc) going down the road but now it is missing at idle. I'm thinking maybe I pulled loose a vaccum hose when I replaced coilpack or perhaps new plugs are needed. At any rate, the check engine light is back on and i'm headed down to AutoZone shortly to see what this code reads. I'm guessing its gonna say "#4 misfire" again! Why can't it be one thats easy to get to?

 

Don't be surprised if it's a "lean" code, IE vacuum leak.

Steve

 

A flashing CEL indicates a misfire. Go get your codes read and start replacing plugs and wires.

 

Yep now it's right bank too lean code! Gonna have to check(or replace) vaccum hoses.

Good call Steve

 

yep kids same thing... hooked up the ole code reader.. misfire on cylinder #4... so i have a set of plugs and new wires to put in it.. it is time for plugs (100K) and wires are original (200K)... some oil on the valve covers but no water in the oil, no water on the ground, no water on the engine anywhere (valley, valve cover, etc)... sometimes it is worse than others.. been taking it out of OD and it is better but still missing at idle in gear.. and under load... has no *****... this agian is a 98 4.6L. so i know what my friday evening shall consist of... 3 or 4 beers and musical extensions and universals...

if it comes down to water in the cylinder, which i shall see when i remove the plugs... and i have to remove the damn intake.. this thing is probably gonna get supercharged... she has at least another quarter million miles in her

BTW, instead of using WD-40 to keep moisture out get yourself a tube of dielectric grease... and squirt some in each plug boot and put em back on the plugs.. it'll keep the moisture out and unlike WD-40 it won't "evaporate" over time...