Yea, I was pleasantly surprised too. I am going to try and borrow a vacuum gauge and see if I can pinpoint a leak. I have to find a good video on that since I've never done it before.

I am wondering, what are some ways I can test to see if my valves are bad? I'm gonna pull the valve covers to replace the gaskets, but I am wondering about burnt valves or something. Is my only option to pull the heads? How does a vacuume auge help with pinpointing bad valves?

Thanks.

 

Do a cylinder leakdown test. That will give you a good idea on if your rings or valves are marginal/bad. Of course, you need an air compressor for that exercise....... Shockingly enough, not everyone has one.

 

Ok, I don't have the leak down tester but I can see if I can get someone to do it. Let me say that this problem began when I was driving and I was driving pretty hard. You know, giving the vehicle a lot of throttle to keep up with traffic and stuff.

While flooring the van, it went quiet all of a sudden. Now, it didn't die, it actually still drove and accelerated as expected, but it was absolutely silent, like I was driving a hybrid or something.

It drove like that a few minutes and then I could hear the engine again. Keep in mind there was no real noticeable change in power or anything. Mind you I was driving at around 40-55 mph.

I drove a few miles home and then a few days later when I drive again, I get the p0303 error and here I am.

I dunno if that story would help narrow what the problem could be?

Thanks.

 

Sounds like a clogged cat, or, one that's working on it.... except the no change in power.

 

Yea, I was wondering that too, maybe there was a sliiiight change, but I didn't notice it. I was in traffic.

Seems like I may have a few issues. I replaced my valve cover gaskets since there seemed to be a slight leak from there and I noticed there were some bolts that weren't even tightened. I could easily rotate them with my fingers. These bolts seemed to be in the harder to reach places. So whomever did the last gasket replacement, did shoddy work. I torqued everything down to spec and it seems my vacuum numbers are better. After warming up and left idling, the number was stable at around 19. I need to double check it though.

I'm also wondering if oil was getting into the plug.

Anyway, hopefully that is one issue down.

The missing is still parent at over 45mph and randomly at low speeds when I give it throttle say from a stop light and I go slow like 20-30mph.

I did drive it without the o2 sensor and same issues. I checked the cat with a temp gun and the intake side was like 550F and the exhaust side was hotter (can't give a number cause I think it went past my temp gun's range though I am not sure what that is). I am sure the cat is probably going bad or bad, like you said. I think it is original and the vehicle has 110k on it.

I think I will give a muffler shop a call tomorrow and see if they can look at it and maybe replace it.

Any recommendations on a cat?

 

Muffler shop should be able to tell you if it's bad or not. They have the right toys for just such an occasion.

 

I got mine from All Computer Resources Inc in Florida 5 years/30,000 miles ago, haven’t had a pcm related problem since.Reasonable price and Lifetime warranty as well.

I would highly recommend them because not only do you get a good bench tested rebuilt but you get exceptional phone tech support even BEFORE you buy to make sure you actually need one, to help you do the job right as well as if you have any questions/issues afterwards.
good luck getting that kind of help from your basic parts supplier.
My truck started frying the coil not long after installing MSD, not only that it started throwing random codes of all sorts as well, they helped me trouble shoot every doggone part til it became obvious nothing but the PCM was actually malfunctioning.

If you fail to correct the cause before installing the replacement you void the warranty.
Their phone number is 1-866-699-5230
I don’t think you will be disappointed.

 

Bought mine on eBay from seller named
"Importapart" for $208. Large selection and seller asked for my VIN and mileage to "flash" unit whatever that is. No problems a year later. Good luck.
Had some of your symptoms and was diagnosed with bad fuel pump regulator. Replaced it and good now also had my cat converter replaced and I'm almost sure that's when my pcm went out. If you get new cat. conv. make sure the not only disconnect neg. bat. terminal but PCM also. I got home from cat conv replacement and van didn't run again until PCM replaced- prob the tig welding electricity. Called shop and they fessed up they didn't disconnect anything.

 

Thanks everyone for the info. The van is running great right now. Just came back from the Bay with the boat too. Turns out the coil had a crack in it, maybe from when I replaced the ignition wire. I found a cool mechanic that didn't even charge me for the diagnostic. Just asked for some good reviews and to bring it back to him if anything else happens.

Thanks again. Funny thing is, I called the PCM company where I bought my remanufactured pcm and they said they would call me back about the warranty inf, BUT they NEVER did. LOL

So I'm glad I don't have to deal with that.

 

Never ever ever buy a PCM or anything from https://www.autocompdirect.com/

They knowingly (my opinion) sold me a bad PCM, then charged me a $125 restocking fee. They have horrible reviews online. I was in a pinch and took a risk and paid for it.

What a racket they have, sell s h i t products and get paid $125 for it. They were complete ******** on the phone too.