low on power when it downshifts

[TexasT]

Well, we got the oil leak and pressure switch knocked out with a replacement. Car starting but still doesn't bust off with authority. It takes a little cranking to get it.

Hooked up the scantool for the ride to work. At idle we were getting 6-7 grams air and it jumped to 117 with more throttle and tps went up getting on the highway. Crosscounts were counting up like I think it should. Integrator was moving up n down between 120 and 133. Blm was moving a bit 128-130.

This was discovered on the way home yesterday. I put the hammer down and it down shifted but seemed to have problems "making hay". It shifted and just didn't have the guts i would think it should have.

Was thinking maf but it seemed to jump . Will do wot after work to see. Maybe coil pack possibly timing set.

Your thoughts? TIA

[Steve Wood]

in Park, what does your maf read at 2000 rpm?

What do the O2's read at wot when you downshift?

What is the vacuum at idle in Drive?

[TexasT]

The maf is showing 15-16 gr/sec at 2k. It drops back to 5 gr/sec at idle.

I brought my "less expensive" meter and was gonna try to get an ohm reading from the could bug I guess I need my more expensive meter for that.

Vacuum at idle is 16 in/hg2 pull it into drive it drops to 12 in/hg2

I'll post back when I get an ox sensor reading

Thanks for the help.

[Steve Wood]

the maf is reading about right for 2000.  Usually the coils will cause an obvious miss when you go wide open throttle.  You can ohm them and see if they look right .

The vacuum is pretty low in Drive...Usuall y 18-19 in park...and about 15-16 in gear if the engine is warmed up. 

[TexasT]

While I didn't see the maf get to 255(wasn't paying that close attention.), but I did see it at 100 and it moves around so I think the maf is working even though it is a stock piece. 

During a WOT blast or two the O2 drops quite drastically. Down to 44 and 39 though it jumped back up. Might get a new one. It was driving 500-750 and went up to high 800s while siting at the lights. All over the place. I'll try to so some searching to learn what this means. Now that I am sitting idleing in the driveway it is in the low 700s.

I'm going to help the neighbor get her mower running and get out the fancy fluke and get some readings on the coils and put the fp gauge on maybe he fpr is having probs.

Again thanks for the help.

[Steve Wood]

double check the wide open throttle maf numbers...shou ld be at least 240....if it is short on range, and that is pretty common, it will then give you the O2 numbers that you are seeing...

[TexasT]

I will do more testing. It is the original maf.

I thought about it more and the timing set has 80k on it. Replaced it around 60k when I did the rear main seal and the pan had a bunch of teeth in there. Also has original valve springs so they may be tired as they are at 140k or so. It just seemed to have more pep when I first put the trans in last year but now we have racked up more miles. I have a set of 980s but wanted to pit a 4.1 together. Maybe it would be a good idea to pit them in.I  read some of the bison posts and know I don't want to pull the heads to try to get the installed heights figured out. Would it be good to just pit them on or leave well enough alone?

[Steve Wood]

whether it has anything to do with the current problem...pret ty sure it does not...but, I think it would be a good thing to put them on.  Will probably run a lot better over 4000 rpm...

[Scoobum]

Those springs were wore out 137,000 miles ago. Toss a set of 981's on it. They'll soften a little bit after a couple of runs. If you're racing your car fairly frequently, I recommend changing them once a year.