lack of power

[jim56]

A while back my '97 ( 120,000 miles)started to miss a bit and run sluggish. I went ahead and had them replace the plugs, wires and fuel filter- all factory stuff. Now it doesnt miss, except when I first start it, sometimes it kind of hesitates backing out of the driveway first thing in the morning. But it just doesnt seem to have anywhere near the power it used to. When I floor it under load , it doesnt miss, but i sure seems to go flat the higher it trys to rev....any suggestions??????

[dsatt12]

This is all theory mind you, but I asked my mechanic about identical symptoms when he was doing some other work. He told me it's probably a cumulative effect of carbon buildup at various places, other gunk on sensors throughout the engine, and flow getting restricted through my well used catalytic convertor. Since I declined to let him start swapping things out, that's about as far as we got.

I noticed some marginal impovements running a good fuel system cleaner through mine. I had a chunk of carbon get lodged in a spark plug was how I knew I had carbon buildup issues. It cleaened that out really well, gave me about 2-3 mpg economy increase, and got rid of an intermittent SES (at least for a few months). I used BG 44K, but many others have recommended Chevron Techron. They are both about $20.

About all I can add to that is that it really doesn't seem to be getting worse. I'm up to 180,000 miles now and that was at least 40,000 back. I'm leaning toward gunked up sensors, since the poor running after the start gets noticeably worse if the car sits for more than a few days at a time.

[newscarver]

fuel pressure regulator... you will read all about them here,if you smell fuel in the vacuum line to it,it may be faulty

[jim56]

I had them pull the code......It is saying mass air flow sensor......but they dont find anything wrong with it.........could the FPR still be the culprit

[tjm]

Vacuum leaks are likely the culprit for your drivability problems; I had the same problems. I have replaced both rubber ends of the PCV plumbing as well as the PCV valve. Check ALL vacuum lines for cracks etc. Also, check that the intake manifold bolts are ALL snug; mine were all less than hand tight (i don't know the torque spec). These cheap repairs fixed all my problems as you described.

The FPR's tendancy for failure on these cars is so high that it should almost be included whenever a tune-up is done. You can check the FPR vacuum line for any gas; then you know its leaking (replace it). If there is no gas you know it's not leaking but it may still have a functioning issue.

Check all the vacuum stuff first.

[tjm]

vacuum leaks can be a typical root of Mass Airflow Sensor codes as well

[jim56]

Ill check all those things out when I get home tonight..

[jim56]

How difficult is it to get to the intake manifold bolts?

[tjm]

eazy but you will need a deep socket to snug the studs that the plastic "Engine Cover" fastens to.

Remove the plastic cover (4 black plastic nuts) and then just go back and forth (one side then the opposite like the way you would a wheel) and snug up the bolts.

If you don't have the torque spec (call your dealer if you can) be careful and use a ¼" ratchet with 2 fingers only! The intake is plastic and I'm sure big $$$

[jim56]

The 2 bolts on each end of the intake were less than finger -tight.
also ,3 of the studs that hold the engine cover on were loose ( do they help hold the intake down?) Thats as far as I got tonght, Ill drive it a day or so and see if the SES light goes out, but ii is already much better than it was- I just still dont think it is running 100%, especially close to red-line . Ill double check all the
vacuum hoses this weekend. I think Ill just replace the FPR considering the miles on it, What do you think???

[tjm]

Sounds like you are in the right direction. Those studs DO hold down the intake manifold. After you have found all this vacuum leaks, give the puter a few days to recalibrate itself (that's what it seemed like to me) and you should notice a difference in everything from throttle response to transmission shifting.

FPR is easy and short $$ and probably a good idea if its the original.