cookj

No leakdown testing tonight; got off late so only able to perform fuel psi check. Went to Autozone and bought Actron fuel pressure test gage, model# CP7818. Removed ignition wire,located schroeder valve and hooked up gage. Turned key over to start. While listening to pump, gage registered 64psi; as soon as pump turned off, gauge dropped to 59psi. Bled gage and repeated three more times; gage psi was 64 psi each time. Bled gage.

Started truck and let idle; while idling, gage registered 55psi. Revved engine around 2000-2500 rpms and gage registered 55psi. I did this a few times and turned off. With truck engine off, gage showed 59psi. Ten minutes later, gage showed 55psi. Another ten minutes, gage showed 50psi. After a total lapse of 1 hour, 10 minutes, system pessure was down to 30psi. I am assuming fuel pump, injectors, poppet valves and regulator are in good shape.

Pulled idle air control valve; it was black (carboned) and cleaned it up. Went ahead and ran to Oreilly's and bought a replacement. After installing it, I started truck and immediately noticed it was idling around 500rpm. Drove it down the interstate and came back home. Rpm's were still low (350-400rpms) and truck died after shifting into park. Immediately started truck and let idle for about 5 minutes; idle increased but still low in my opinion, around 500rpms. Pulled ground wire from battery; thinking pcm will reset. Will re-attach in the morning and report back. thanks

cookj

Hooked up battery this morning and started truck; still idles around around 550-600rpm with the occasional hiccup. Shifting to reverse, rpms drop to around 300-350 and feels weak. After backing out of driveway, shifted to drive with the brake on; same situation as in reverse gear. acceleration feels similar to as before but coming to a stop, engine rpm drops below 500 and fluctuates between 350-500 until i accelerate.

Got home this evening and pulled IAC; repeated procedure for cleaning TB and IAC port (although it was clean already). I connected harness to IAC and turned truck to "ON" to see if plunger was working; it was. Based on some reading i did today, hooked everything back up and turned key to "ON"; i waited 20 seconds and turned key to "OFF". Waited another 10 seconds and started truck. Truck idled fairly smooth around 600-625 rpm but I could still tell there was something not right. While applying the brakes, shifted into reverse and truck acted like it wanted to die; again, rpms were around the 300 mark.

I don't know, this is getting frustrating. All i did was replace an original part with a new one and now i have another issue (or mystery) to solve!! Where does it end...

cookj

Due to my work load and schedule, I haven't been able to post till now. As for the IAC, ended up replacing it once more with a Borg Warner (?) and truck idles like it should now; I was refunded my money on the other brand. As for performing a leak down test, haven't done so yet. Think i'm just gonna buy a longblock and be done with it. Due to funds (or lack of), thinking of a new L31. I've read up on the HT 383 and other mods I could do to this L31 to up peformance but cannot afford to do so at this time.

So, my question is, will a new L31 with shorty headers, CAI and possibly a retune (or tuner) be sufficient for everyday driving and on occasion, towing this Jayco? Thanks!