Folks, I've had my '95 1500 Ram since 1996 and it's been a great truck! But now I have a problem that my mechanic can't figure out and I hope someone here can advise what else we can try!

I'll be driving around for an hour, making some stops, truck's running fine, then it'll do the chug chug where it feels like it's running out of gas, This has happened three times now ... After an hour or so it'll start again,

First he replaced the fuel pump, then the cranksaft position sensor. I still have the problem. Now he's replacing the computer, thinking it's old and the engine heating up is causing the problem. What do you think? Is there something else we could be missing?

 

Checked the plenum?

 

NO! What's the plenum??

 

I googled that, I'll tell my mechanic!

 

After reading up, it looks like it could just be the gasket, is that what usually goes, or is it the whole plenum we'd need to replace? I need to order some parts!

 

OK my mechanic doesn't agree with the plenum,

so could it be the computer?

 

How many miles on the truck? Do you drive a lot on the highway or just short trips around town? Before you throw money at the issue, lets do a little trouble shooting. If you only have 50,000 miles on the truck, the timing chain is probably good. If you have 150,000 miles, I would check the timing chain for slop. It might even be making a rattling noise in the cover. Your mechanic can pull the cap off the distributor and mark the location of the rotor. He can then mark the balancer and rotate the engine backwards by hand. If it only has a couple degrees of slop, it's good. 10 degrees for instance, it needs a new timing set.

If you have the original exhaust though, and you drive short trips a lot, I'd hook a vacuum gauge to the engine. I would personally install a vacuum/boost gauge on the dash. You should be pulling 17 inches or so of vacuum pressure. If it drops while it's chugging, you may have an intermittent blockage on the exhaust. With the exhaust cold, crawl underneath and thump on the catalytic converter and muffler. If you hear a rattle, the muffler, and or, the converter might be rusted inside.

 

No I'm a general contractor and have put 250,000 miles on it, hauling loads, it's been a real work truck! No unusual sounds are coming from the engine.

could it be the computer? Worth a try? This only happens after it's good and warmed up.

 

It wasn't mentioned so we gotta at least ask: are any codes present?

Does it only die when you're on the accelerator? Will it do it idling? What's fuel pressure like during the event? Have cap & rotor been replaced?

PCM isn't the worst guess but it's always a bummer to throw a new computer at something and NOT have it fix the problem.

 

Another mechanic, back when this issue first started, kept it ideling for 1/2 Hr, saying he had to wait for it to shut off in order to read codes, but it didn't. so no, no codes have been read.

Yes it does it when ideling, and maybe when I let off the gas when slowing to a stop?! Feels just like running out of gas.