Sorry this is really long but I tried to input as many details as I could. Thanks in advance!!

Everything started going downhill after I got a tune for my car. Before it ran decent, just at about 9 mpg. I got my pcm and put it in, right off the bat noticed a few things wrong with the tune. Finally worked things out and took it around town; it ran better than before. First time I take it on a country road and get on it 1st-2nd-3rd-4th and then slow down and my a/f (cheap non-accurate gauge) drops all the way to lean and sticks there. I know they aren't good gauges but I could feel the major power loss and it was a struggle to get home. I would turn it off for a couple minutes and turn it back on for it to get a little better than coast the rest of the way home. After complaining to the tuner they said its a bad pcm and they sent me a knew one. Plugged that one in and it worked fine for a couple days this time, but once I took it WOT in the country it did the same thing. Could this be fuel pump?? Drove fine the day after around town at part throttle until a week ago when it was really losing power all over and it sounded like it wanted to die like a *cough cough*ing noise or something while its in neutral going about 5-10mph. I put a new fuel filter in and injector cleaner but it still does it, but now all the time?? I can't figure out what's wrong, if its optispark or if it could be the fuel pump? I checked pressure at idle: 38-39 and just revved it by the tb and went up to about 42 then back down. Any ideas?? thanks

-Chris

 

Who did the tuning? What is your FP at WOT (reading with the vac hose disconnected from the FPR). Normal is like 43-46 and about 8 less with the hose connected.

You state that things went down hill "after" your tune---what does that tell you? JMHO

 

ion at madz28.com tuned it...? i'm going to need a longer hose on a fp gauge cause with mine i can't get it up to the windshield to tape it. I'll borrow one from my friend at a shop in town and check it at WOT though. I forgot about taking the hose of the fpr. So if it goes down at WOT then the pump is going bad, right? It almost feels like a constant miss but I just put taylor otvc wires and tr-55's on about 1,000mi ago and like i said it worked fine before the new pcm. I'm going to put the stock pcm back in today to see if it helps but I have a feeling its something mechanical this time..

-Chris

 

Well, you don't need to tape the gauge to the windshield----just hook up, read it with the hose off (43-46) with hose on about (35-38). Tuner probably tuned based on the ususual stock pressures----you don't need to rev it up, just read it at idle.

Your FPs don't sound that out of whack, but with your MPG I'd say it was runnning pig rich. Maybe your 02s were boogered---bad 02 will show excessive fuel consumption, hesitation, surging---all kinds of crap.

Your PCM was probably tuned just fine, but you are right---something else is amiss.

Good luck.JMHO

 

isn't it more effective to see what the fp is under a load though? that's when fuel consumption is going to be the greatest..or am i wrong.. thanks for the tips though i've got a few things i need to check out asap

-Chris