Those who have read through most of my threads on this journey with this truck would know a lot of work has been done on this motor. I've been dealing with a light rough idle. ( You can feel it but rpm gauge barely shows it) It does a off and on misfire that you will feel here and there but bad enough to throw a code. When I replaced the plenum and intake gaskets about a year back. I did a full tune up from cap to plugs. I have maybe put 2 to 3,000 miles since then. I have replaced about every electronic part on the throttle body. I have a new map sensor coming in since I think that is only part that hasn't been replaced. New fuel pump a few months ago (cleaned tank out at the same time). Since we have a 3 day weekend. I am going to pull the plugs and get a good look at them. Maybe may have a bad plug or plugs? I may just pull the throttle body as well and give it a good cleaning and blow it our with the compressor. Then go from there.

Also dealing with odd shifts. Sometimes good then sometimes erratic but was thinking about it and remembered I didn't replace the speed sensor when I rebuilt it so going to get that replaced Hopefully that settles that issue as well.

 

What plugs are in there?

 

I want to say Auto lite but can't remember to be honest. Going to pull them weekend Figure I would take a look at them. Thinking I might do a good throttle body cleaning as well.

 

Can't hurt. These trucks really don't like the rare-earth plugs though, so, if you have 'em, change 'em out for some plain ol' copper plugs.

 

I think they are copper but I may be wrong. It wouldn't hurt to replace them with new one's and see it improves. Thanks

 

I didn't get the chance to do the plugs this weekend but did replace the map sensor and output sensor on transmission. I figure I will do them this coming weekend. Anyway, I took the truck for a drive on the highway this round for about 12.5 miles. Over all it shifted pretty good. I did notice 2nd to 3rd seems a tad bit long but I don't want to adjust the current TV cable since I haven't had much luck there. The best way to explain it would be the shift seems to drag out longer then other shifts. If that makes any sense? It's not bad about around 2,000 rpm maybe a little higher at times. This is around 30+ mph. Most speeds around here are under 45mph. I am looking into getting a new TV cable this coming week. My guess is the old one may be stretch a little and is why adjusting it is a pain. Slowly making good progress here.

I do have a question though.I know the coil has never been changed and I was wondering if maybe it's a little weak would cause the idle issue? it starts good but every now and then it wont start but after a couple of tries it does.This usually happens on a short runs. I'm not sure how to test it? Thanks

 

Grab a spare spark plug, hook it to the distributor end of the coil wire, ground it somewhere on the engine, crank the engine. See what the spark looks like. Ideally, it should be a fat, blue spark, that snaps. Rarely do I see that though, even with a brand new coil.

 

I will give that a try this weekend. I asked due to age of coil. Its never been changed and you're looking at 20yrs. lol. It's not a real bad idle but it's noticeable. Just finding what would be the cause is not fun. I did a full tune up when I replaced the intake gasket with the upgrade since it was easier to get to. Never was a fan of distributor being behind the motor. Thanks again.

 

These engines don't idle smooth. There's always a little bobble in the RPM. The best plugs I ever used were Champion Truck Plugs but they were discontinued a decade ago. Just stick stock plugs in and run it. Or keep throwing parts at it. If it doesn't die at a light or bog or get terrible mileage, it's fine.

 

This motor has ran in the past pretty smooth. I'm just getting a gentle misfire/idle that shouldn't be too much to correct. As to throwing parts at it. I am only replacing parts that have years on them. I don't mind since most have done there job for years. Those who have read my post from past to present, know I have done a lot of working getting back on the road and driving. I have done both engine and interior work. Hopefully by the end of the year, the dash will be completed, new headliner and seats will be done. Will do the coil test this weekend as Hey You suggested and go from there.