curtiswyant

Hi all, I've got an '87 22r (carb) truck that's been running rough for awhile. At idle and "cruising" RPM there is a consistent miss, I think, it's hard to tell, just sounds like the engine is "puffing." The roughness is absent or at least less noticeable during acceleration. The exhaust also smells. I've replaced plugs/wires/dist cap/rotor/PCV/fuel pump/fuel filter, but no luck. I used Bosch V-power plugs. I've checked for vacuum leaks and checked the valve adjustment, which was within spec. I've also messed with the idle speed and timing advance. However, I don't know what RPM the idle is set at, so the timing may be off...here's some stuff I'm planning to do:

install new/reman carb
reset idle RPM w/dwell tach, reset timing
replace all vacuum lines
replace plugs and plug wires with ?


Any other suggestions?

MMA_Alex

i would check the timing. a lot of people swear by ngk/denso plugs, and I didnt think much of it till I had issues with my autolites. I would recomend switching to ngk or denso.

91RN81

definetly change over to the ngk or denso plugs, made a big difference between some other plug i had used. The idle with the ngk's was night and day, weird. Also check the carb, many guys have problems with the carbs on the older 22R motors. It just needs to be rebuilt or replaced. They are expensive new. good luck.

MMA_Alex

the idle between my ngk's and my autolites was night and day too. oh and the ngk's were gapped right out of the box

keithguts

Ok let me start off by telling you I had the same problem, and did everything you did with no luck at all. The wind up was that it had a bad exhust valve, that was causing my problem. It is in the shop as I speak. Please keep in mind that my engine is a 3.0 and it is a 95 runner. Did you by any chance do a compression test on the rig. I wish you all the luck. look forward to your posts on your findings.

curtiswyant

I'm planning to do a compression check soon. I hope it's not a valve issue, but at this point, I don't care what it is, I just want to know WHAT it is! Upon further review, I actually used NGK plugs so that shouldn't be an issue. I'm pretty sure it's timing/carb/idle speed related...

curtiswyant

Success! I think. I did a compression check and got about 175 for cyls 1, 3, and 4. Cyl 2 was low, around 110. The spark plug from #2 was severely melted so I replaced the plugs and plug wires. Fire 'er up and it idles smooth and runs like a champ! Now, I'm thinking the low compression and melted spark plug from #2 is indicative of further problems (burnt valve, intake leak) so I'll keep an eye on it. But for now, the truck is running great, timing is spot on, and the idle is smooth.

curtiswyant

Now that I think about it, the low compression on #2 may have been because the cylinder was cold (assuming the spark plug wasn't firing, or was giving low spark). I'll do another compression test soon after the engine has been running good for awhile!

ToyYoda

Pour 1/4 can of seafoam down the PCV while the engine is running if you can. The goal is to soak every runner with it. It will smoke like crazy (I like to dance around in the smoke, it's more fun that way) then kill the engine, let sit for 5 minutes and fire it up again, it will smoke, again, for a while. Also, check the sides of your engine for smoke and seafoam pouring out of the head gasket. That's how I found out that my low compression was from a blown head gasket that didn't blow through a water port.