Like I say, your valve cover is probably leaking anyway, they usually always do,so get a upper intake gasket, and a valve cover gasket, pull the plenum, and check it out

 

Ok, Riddle me this. It may be a fluke as I havent put it to the hot rod test yet, but I switched tanks to see if the 300 year old gas would burn (got tired of looking for a place to dump it, it's at least 1+ yrs old) and Ive put on about 30 miles since without missing a beat. I thought old gas was supposed to make it run WORSE! It purred like a kitty kat! Granted, I've dumped about 1 bottle of lucas fuel stabilizer, 1.5 bottles of sea foam, probably a gallon of whatever else i could find, and 2 gallons of fresh gas. The fuel pump is a little louder pumping that pudding and its still under powered but other than that it runs perfect.

I dont get it. I guess thats a testiment as to how impervious the 300 is to whatever you can do to it.

 

"I dont get it. I guess thats a testiment as to how impervious the 300 is to whatever you can do to it."

There is a lot of subjective mythology about the 300 out there that runs along the lines of: "bullet-proof", "indestructible", "torque monster", etc. Most, if not all of it is ad infinitum, reductio ad absurdum, ad nauseam.

I find it productive of good results to ignore it.

 

interesting...maybe the pickup in your front tank is partially plugged up?

 

Hummmmm...........

Could be the tank selector (in the dash) switch........

Or, could be ( click this link ):http://http://sbftech.com/index.php/topic,15654.0.html ( failing ecm's and the repair ).

Just a couple of things for you to check.

Good luck !!!

Bob

 

might be worthwhile to put a pressure gauge on it, and see if you get a better reading on the rear tank. i've read things like small splits in the pickup tube sucking air, etc.

 

For the fuel pressure test you can rent the tester from autozone for $150 (i know it's pricey but you get it all back when you return it). It's really easy to hook up, the shrader on our 300 is on the back side of the fuel rail right by the firewall.

Simply screw in the adapter, move the gauge to where you can see it from the cabin (I used my windshieid wiper to hold it down where i wanted it) and key on and off a few times until it stops building pressure. you can also switch tanks and see if your pressure is dropping.

 

I initially thought TFI module, u said u have a new one...what color is it? I would remove the TFI and have it tested, make sure they test it several times in a row. Could also be the pick up in the distributor. My dads truck had similiar issues for years, hit and miss...would run great for weeks or even months and then it would go ape****. His issues were at part throttle when he gave it more it would fall on its face, buck like it was missing and/or loose all power and he let off. Once he got back into it, it was fine. It was more prevelant when going up a small grade, but would do it randomly anytime. It threw tons of erratic codes, i chased my tail for years then i broke down and decided it was time to seriously dig in. I found a TSB about the shielding wires grounding out in the pigtail leading to the remove TFI module (his is a 95). So i tore it all apart and found nothing. Replaced the TFI since it tested OK but i wasnt confident. Finally i dug out my old hayes manual and tested the entire ingitnion circuit, finally came up with a faulty PIP in the dist. Ended up replacing the dist and its been great since (knock on wood).

With yours being an 88 and the TFI on the dist, they are known to get heat soaked and go FUBAR. I would also look into testing the fuel pressure. Make sure u test when cold, engine off; engine startingl engine running and then engine off after its been pressureized to check for bleed off. Fuel pressure should be 45-60 psi. Another thing to check is the pressure regulator, pull off the vacuum hose and see if the hose is wet. Could indicate a ruptured dispham. Those tests would rule out anything on the fuel side short of faulty/bad injectors.

 

I FINALLY replaced the ignition module. Runs like a CHAMP!!! Well... if you factor out the dirty fuel filter that is causing it to die. BUT... I drove it for about 50-60 miles with no sign of a miss or stutter or stumble. It was running more smooth than it ever has before. I actually killed it at a stop light because i couldn't hear it running even with the radio off. So now I need to put in a new filter and get the fuel gauges working and she'll be as good as new (mechanically), (almost). Thanks for your replies everybody. I appreciate the input.