Can anyone help me get this truck running correctly?

[AustinBelair]

I don't have any cool or pretty pics to post but I need some help. I've been trying to get this 87 V6 TBI truck that I bought recently to run good. I had a code 32 at first which is EGR so I bought a new EGR valve and solenoid. The code 32 is gone but I am still having some kind of issue.

When I first start it it fires up and idles okay for a second or two then stumbles pretty badly then idles up and it kind of evens out then idles okay. I can hear a clatter under the truck briefly and I have a pretty bad vibration at idle. When at a stop light It vibrates pretty bad then as I gas it, it feels normal. It also feels better in park or Neutral but you can tell there is a vibration still.

The only other thing I have noticed is a FUNKY foul metallic burning smell when I drive it around the block. Not a rotten egg smell like a bad converter but it's almost bad enough to make you want to choke. I smelled the tailpipe and it's definitely coming from the exhaust.

The trans (TH350) fluid looks good, the oil looks good, power steering fluid is topped off. Flexplate looks good and was replaced 7 years ago. Did not see any cracks or defects. Converter bolts were tight. Does not appear to be a counter-balance shaft engine. Harmonic balancer does not wobble at all. Belt stays true and straight at idle. At start-up when cold I have a puff of smoke so I am assuming valve guides or seals.

So far I have replaced:

- Most of the vacuum under hood with silicone high temp hose
- EGR valve
- EGR solenoid
- TB base gasket
- 6 Spark plugs
- Air filter
- Passenger side motor mount (Still need to do drivers)
- All cab and core support mounts with poly
- Starter

[AustinBelair]

I forgot to mention

If it's running and I smell the exhaust coming out of the tailpipe it STINKS of fuel.

[Dead Parrot]

Not a FI expert but sounds like either a misfire in a cylinder or one running rich. Since you recently put in new plugs, pull them and inspect. If you find one or more that are black or oily, you will have found the problem cylinder(s). If all look rich, then probably something wrong with the TBI setup.

Might check the plug wires and cap.

[cadillac_al]

My first gut feeling was a clogged catalytic. The shaking at idle makes me think MAP or O2 but that should set a code. If you have never inspected the dist cap that would be suspect. The first thing I would do is see how much vacuum it's pulling. If vacuum is low all the time it just may be the catalytic (or leaky vacuum line).

[AustinBelair]

I pulled vacuum and it started at around 16 at idle then slowly crept up to 20in at idle. I am going to check timing this week and ordered two O2 sensors just in case.

When I pulled the 6 plugs they were all mostly black and a few smelled faintly of old gas. I sprayed some Seafoam spray in the TB while my dad kept it at idle. Didn't really help much.

[cottonme173]

I would definitely open up and check the distributor. Since all of the plugs look about the same and smell of gas they may not be getting the correct spark (week or intermittent) and not burning all the way. This can cause the shaking and issues you are describing. Hopefully it's that simple! Let us know what you find out!

[AustinBelair]

I haven't checked the dizzy yet but

I'm a little confused on this timing tab on this thing it only shows 0 to 12 so I'm not sure if that's before top dead center or after top dead center. I'm pretty sure I found the correct tan wire, disconnected it and loosened the distributor. When I set the timing gun on it it was showing 10 to 12 degrees and it should be at zero as far as I know. I set it to zero and killed the engine. Tighten dizzy bolt and disconnected battery for 5 min. It seems to run a little better but still has the vibration and idling a little funky. I am going to order a MAP sensor and a cat. converter tonight for it and replace those next week.

[AustinBelair]

Installed a new oil pressure sender and now my factory oil pressure gauge works. It's around 20-30 at idle and around 40-45 cruising.

I drove it and got it hot. I got my infrared gun out and the inlet cone of the catalytic converter is roughly 440 degrees and the outlet cone is around 100 degrees hotter (545) so as far as I know, the cat is working as it should.

[AustinBelair]

I can put it in Park or gear and have someone hold the brake and I crawl under the truck and feel the transmission/driveshaft and they are vibrating. I think the source of the vibration is the engine or maybe the transmission. I also noticed that when leaving a stop, the trans whines pretty good from 1st gear to 2nd and if I hammer it while driving the trans really screams/whines. Sounds like I have supercharger.

[Dead Parrot]

Your test run that showed 20 inches vacuum at idle is a good number. Since all the plugs are black and wet looking, sounds like a too rich problem.

On a computer engine, could be an bad O2 sensor sending a lean signal and causing the computer to go rich to fix. Or could be a knock sensor malfunction and causing the computer to go rich or retard the timing.

There should be a sticker somewhere with the idle timing. If sticker missing, a good start point is 8 BTC. Measured with the vacuum advance disconnected and the port capped. Most stock motors like a lot of timing advance.

Cheap thing to check is the little button on the inside top of the distributor cap. If worn out, can cause all plugs to misfire.

[DieselSJ]

First, check spray patter on injectors. With it idling, you should see a fine cone with no drips or streams. When I first got my truck, my injectors were leaking badly and I had similar symptoms. Some new o-rings fixed it.

Second, buy a ALDL cable and download a free copy of something like winaldl and look at everything while it is running. Mine was throwing a EGR code and I replaced all of the EGR pieces and it still got the code. Finally got winaldl running and found 2 codes that were not showing up when I used the ground a/b pins and read the flashes. One was TPS low (was out of adjustment) and the other was for the spark timing. Traced the timing code to a bad ignition module. Have a new module on the way. I would have never known if I hadn't hooked it up and looked.

Got the cable from here - http://www.aldlcable.com/ and it came with a CD that had like a dozen different software programs on it.

[AustinBelair]

I can't afford the cable just yet but I did check the injectors spray and they look uniform and good. Turn key off and no drips from injectors.

I realized today that after driving it 66 miles that the radiator hose was not real hot and the upper radiator hose was hard. It seems like maybe the thermostat is not opening? The heater works pretty well so that is odd to me.

I bought and replaced a new coolant temp sensor today and installed a new catalytic converter. Also replaced the cap and rotor. Seems to run better but still has an idle vibration and the only code I am getting is still 45 which is a rich condition I think.

[AustinBelair]

Today I installed a new 195 thermostat a new O2 sensor and a new IAC and it runs great! BUT still has a bit of vibration at idle. I am convinced it's a bad engine or bad transmission or torque converter etc. Something is wrong and it's driving me nuts.

[DieselSJ]

Check the harmonic balancer. This was mine. What totally saved me is that the lower pulley kept it from flinging off.

[AustinBelair]

Beginning to wonder if it's the balancer myself. I know these V6 motors vibrate a little but this is odd