Chevy & GMC Vans

Back in december, van started running poorly on occasion. Like it was skipping on a cylinder or two or running way rich. Give it gas and get away from low rpms and it was good. Seemed to get worse in a few weeks to the point where once warm, it would run bad, same as above. Then a new wrinkle was once warm and driven a few miles, it would start hard. It would crank over and sorta start but quit as if it was seizing on a cylinder or had water in a cylinder. Like something mechanical was abruptly stopping the motor.

Saw a mouse nest on the engine.... gave me hope for a quick fix like repair chewed up wires. But the nest was small, no wires near it. but now van seams to start and run ok. Will restart with no problem. I have not driven it since removing the nest. I looked for sparking wires , coil and see none. Coil, wires, plugs cap rotor are about 2 years old and anyplace that wires could rub, I put plastic wire loom on the wires.

Codes.... found 4, P0300, U1041... electronic brake control module, U1192... electronic variable orifice class 2 communication, P0300. Cleared these, continued driving and it ran worse, stopped at another CP store and codes were P0305 misfire cyl 5 and I forget the other, no big deal. Stopped back at first store on return trip and had 3 P0300.

I am scared of the Security light problem. I have seen it lit up briefly a few times thru all this. I did have a remote starter, alarm added last summer. They had to remove my old alarm .
Not much detail but hoping someone can guide me. I may pull out of the unheated garage and drive it today. Been driving my summer car (73 Opel GT) with NO HEAT since christmas but inspection sticker is the wrong color since 1/1/15. AND its like 10 degrees today.
ETA: All ignition components are delco or the correct pricey stuff we all know we have to use. and on the coil, I painted it white to help see arcing if it happens and I put silicone on nearby metal stuff to reduce the chance of arcing.

Here is a bit more on this but not much. My note from running it today with a scan tool attached.

Started fine, ran up to temp..... 198. Everything looks good on odb II scanner. Shut it off, it restarted sorta ok. ran it awhile, shut off and then.... It is restarting but then has the abrupt stop a couple times. As if , I don't know, mechanical or way off timing.... starts and now is idling at 550-620 instead of 950. Minor off idle roughness when giving it some gas but then sounds fine but wants to idle around 600. No codes but I have not driven it in days just start and run in garage.

P0300 is a fairly common problem with GM V6s and V8s in the late 90s. The injectors gum up after a bit. Problem was frequent enough the GM developed it's own fuel injection cleaner. It's a little pricey, but it's helped even van I used it in. It's Called GM Fuel System Treatment Plus, pretty much any GM dealer should have it in stock.

How's your fuel pressure?

I would start with fuel pressure check then pull the cap off to inspect it and the rotor. After that, I would look at pulling the distributer out and inspect the gear on the end. We have seen quite a few of these bad over the years on here.

If only I could remember that I can't remember crap lately......
So Im thinking I just put all the new ignition parts and filter, etc in the van. Looking up my purchases, I see I did all that stuff in 2011 or 2012 . Short term memory is bad, long term not so.

The other night, starting it hot it backfired and blew my 02 sensor out of the non-fouler that cheats the hollowed out cat.

Anyhow, my "new" parts are pretty old and very worn and dirty. I would post a pic of the distributor but just trust me, lots of old moisture, rust and deposits on most everything inside the cap and under the rotor. I used tons of electric grease on connects and even around the bottom of the cap to seal it and it has been good for twice? as long as is recommended.

So my fix cause it was too late for new parts, was to clean everything up, sand the pins inside the cap and it runs fine, re-starts fine. Need to road test it but not before I crawl under it and fix the 02 sensor and replace the oil lines and run a cable for an amp.

I see a lot of evidence of excess heat at the rear of the engine, is there any info on cooling things down? I use the stock temp thermostat 195 I believe.

Hey Lifted!
I must have been writing mine as you replied. Some day I should get whatever is needed for checking fuel pressure. It has been a few years since I learned Gen 2's are MUCH pricier to pay for replacing!
I put a new distributor in when the plastic ear split where the cap fastens, years ago. This week, I noted one screw was not tight when I removed the cap.... this is the first cap ever installed and the screw hole is not holding. Plastic engine parts baffle me!!!

Well I have to get out in that unheated garage and back to Facebook..... I'll be back with my next van repair questions......

BTW, I'm gonna get a bluetooth OBD II thing to plug in and use on the fone app. I always use a speedometer app when driving already so it will be nothing new except for lots more real-time info!

Anyone else have speedometer issues in cold weather? Mine sticks when cold and I don't trust it. I like to set my cruise for 62 or 63 and I always go thru radar with never an issue. In my Opel GT, the speedo cable has been broken for years and a Civic I sold last summer would read 95 at 60 so the speedo app gets lots of use. I even use it on my street legal dirt bikes. One is broke and the ktm doesn't have one.