Hi all,
I got a '98 1500 4x4 with a 5.9L in it,
It has difficulty starting, when i hold the key it won't start, but when I release the key it will sometime start. I have been starting it by bumping the key, not too good for the starter. When its running it idles all right. if i gentle depress the gas it increases the speed no problem when stopped. But if i mash the gas it will stall, sputter and backfire and then go back to normal when I release the gas. Driving is more difficult increases in engine load can cause it to sputter, and stall when moving from a stand still with any kind of a hill.

At first I taught it was a clogged fuel filter, but have a steady 45-50 psi on the fuel rail at all loads. I cleaned the throttle body, it was nasty. and after some debating with myself I changed the TPS and the IAC. both of these helped. Now the RPM's drop to near nothing, sputters and backfires but stays running. One of the O2 sensors will read high volts every once in a while. The only trouble codes that shows up, is a misfire on random cylinder.

Any help is greatly appriciated
Thanks
Declan

 

Hows the battery?

I'd replace the O2 sensor and perhaps the MAP sensor. What brand of TPS and IAC did you purchase (and where from)?

Get the catalytic converter checked, and check to see if your plenum gasket is blown.

When was the last time you did a tune up? (New plugs, wires, cap, rotor?)

 

I haven't had the truck to long so don't now much on its history.
The IAC and TPS are autozone Duralast specials.
I will replace the O2 sensors, after i check the wiring.
The cat and the exhaust appear to have been replaced. The sloppy welds are a good indicator.
The map sensor is giving read outs on my scanner. Just as the TPS was, I mainly changed the that and IAC because I needed to change something.
The PCV valve was rattling so i changed it first, as well as buy a new air filter.

I'm sure it needs a tune up. I should check the distributor. I do have oil in the air plenum( do these valve have seals.) When I hit the gas hard I get a loud sucking sucking sound. Like it not getting enough air quick enough.

Thanks,
Declan

 

I wouldn't trust Duralast products one hundredth the distance I could throw them. Since you already have them, keep them, but keep an eye on them. Very poor quality usually. Autozone's brand of stuff usually is.

I'd get that converter checked. A clogged cat, IIRC, can caused you to have that sucking sound from the intake, don't assume anything if the previous owner didn't take care of it.

A Felpro gasket and the product below, an aluminum Hughes plenum plate, is the solution to the leaking plenum problem:
http://www.hughesengines.com/Index/p...6&partid=22220