Hey guys I'm hoping you might have some ideas on where to start. I was on my way home today and cruising down the road about 55 when the truck decided to cut off. I had to pull over and then it wouldn't start back up. I went back a little later and it would barely start, but only spuratically jumps from about 200 - 500 rpm, and shuts off if you try to shift into gear. It smells like gas and wants to backfire if I try to give it gas. My disributer, plugs and wires are all pretty new, any ideas? Oh yeah it has 140,000 miles, catylatic converter clogged maybe??????

 

Start with 96+ Fuel System Diagnosis.

 

Just throwing a guess out there. Mass air flow sensor. If you can get it started you can bang on the air intake (MAFS) and the idle will fluctuate, or if you bang on it a little it may run for a little bit. I do not know how to test it correctly, but sounds like it would not be a bad place to start.

What do you MASTERS think?

 

That was one of the first things I thought of. I disconnected the MAF and the condition didn't change. It sounds like it has fire and wants to run, but it's like it's being chocked really bad.

 

If it smells like gas as you said then it is unlikely to be anything other then a leak that has developed in the fuel system. Most likely the pressure regulator O ring or the FPR itself leaking based on what you describe.

 

Thanks I'll check the fpr today

 

OK so I replaced the FPR which was a pain to get to and no change. I pulled the O2 sensor before the cat to free up breathing and that also didn't have any effect. It will turn over and over, but won't start. It sounds like it wants to catch sometimes but won't start. Any other ideas???

Also in case this helps. The truck had been running rough lately. The last few weeks it had been idling rough and would stall at red lights sometimes. It didn't seem to effect driving or power so I wasn't in a huge hurry to get it fixed. Well the last few days it was progressivly getting worse and would stall often when idling. I did start to notice a loss of power and then while driving it just shut off.

Some history on the truck
Fuel pump, fuel filter, Distributer, wires and plugs are all less then 6 months old. The was all replaced when I had to do the intake gaskets because of coolant in the oil.

 

Ok so the latest thing I did was take the coil and icm off and take them to the auto parts store to be tested. They didn't have a way to test the ICM, but when testing the coil they couldn't get a read from the input terminals to the output terminals and told me it was bad. I bought a new one installed it and no change. I'm starting to run out of ideas here any help at all would be appreciated.

 

Did you follow the steps in the link I originally supplied?

 

I would def follow rridle's link, it is a good one. should cover all bases

here are a few of my thoughts:
did u replace the fuel filter when u replaced the fuel pump? Also did u use a quality name brand replacement pump? if u answer no to one or both of these then its possible that ur pump is bad again.

Try spraying a shot of starting fluid directly into the throttle body, if it fires right up and runs for a few seconds then u can be pretty sure that u have a fuel delivery issue and not an ignition issue. Also u should check the fuel pressure with a gage to make sure u are getting approx 60psi. If u have a plugged filter, or leaky line u wont get enough fuel to the engine which explains hte no start and poor performance. It also would explain the odor of gas