Note: I did attempt a search...but not sure what I'm looking for. Sorry.

Hey all,
Here's what I'm trying to diagnose and it's not working.

I was runnin down the road and she lost power. Not running hot...all was normal. Oil pressure good. temp was fine too. Had to bury my foot in the floor to keep it at 55 to get to an exit.
Runs really rough. Like it's running on 3 cylinders.

Knowing enough to do my own maintenance etc...but not knowing much more than that...I took it to a friends shop.
He said it was most likely a bad carb...he doesn't do carbs but suggested I get a rebuild.

Later that day my neighbor, who is also a mechanic, came over. He suggested it was probably a vacuum leak or a bad carb.

I got out my vac tester and went through the Raider manual and checked vac at all places that I could. All seemed fine.
I even cleaned out the EGR valve. It was nasty...but cleaned up good and worked fine.
Replaced the PCV as well. Looked for vac leaks at all the ports and caps.

So I had the carb rebuilt by a local shop that only does carbs. Been doing them for years...everyone I've talked to swears by them. They didn't have a core...so I removed mine and marked all the connenctions, took pics etc. They rebuilt mine.

So last night I put the rebuild on. Replaced the fuel filter and cranked it up. Nothing different than before. Still feels like it's running on 3 cylinders.


What would you recommend that I do next?

Thanks in advance <img src="/forums/images/graemlins/patriot.gif" alt="" />

Fuel filter? Sounds like it's fuel starved. Does it idle smooth? Pull fine up to a certain speed?

A compression test is something else you should consider.

No...it idles rough.
Changed the fuel filter right before cranking it up with the rebuilt carb.
Just spitballin here... could it be something simple? Like a bad plug wire, fouled plug?

Yes. Something I didn't see in your original post. When was the last good tune up? Plugs, wires, cap, rotor, air filter, etc...

Air filter is fairly new.
Hasn't had a tune up since I've owned it (2+ years). The PO said it had been tuned up right before I bought it. This isn't my DD. I've put maybe 10,000 mile on it since I've bought it.

So I should go ahead and do a tune up? If that changes nothing... then a compression test?
If taht changes nothing...then advertise it on Craigslist as a "rare 3 cylinder gas saver"? <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

Sounds like a good path. And get the best tune up parts you can afford. I would suggest NGK plugs and either NGK or Belden wires. On the cap & rotor, go with your store of choice's premium parts.

That "PO says" is probly the issue. Where you at in Florida? I'm guessinmg you're in TB being a Bucs ( <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />) fan. I'm in Jacksonville, but not a great Jags fan (Go Vikings). We have a few people over on the West Coast of the state. Also we have this ( A great event ) coming up in November

The reason I suggested a compression test is that a sticking jet valve will cause the same issue.

The basics are to pull the plugs and inspect them. Is one fouled? Or do they all look the same?


You need spark and compression. If one plug is fouled that cylinder is lacking one of those two.

Two ways to go , try some new parts to see if it fixes the problem or do some testing.

A compression test takes less than a minute and will tell you a lot. If you have good compression than the culprit is probably ignition.

Another test is to pull one plug wire at a time with it idling and see if you have one dead cylinder.

Kevin

Solid advice from Kevin. The only reason I suggested a tune up is because you'll want a maintenance baseline if you'll be keeping the truck. If you may not keep it, then by all means, test before you spend any money on it.