Lvangundy

I'm lost with my car again - don't know what to do.

My power band, which used to kick in around 2800 RPM, has now moved up almost 1000 RPMs! The engine doesn't get it's full kick until almost 4000rpm. Running a stopwatch test (0-60) of 9 seconds now! Car is getting slower and slower, is this a transmission thing?

SOOO beyond frustrated, what's going on?

New plugs, new wires, new caps, new rotors, stock airfilter! Maybe my pluygs and wires just both happened to be bad? I did not have them gapped, I just threw them in there. (torque masters) Is that it?

Also, I'm getting about 13-14 MPG now, 8 months ago, was getting 17 avg.

Lvangundy

Can someone do a couple averaged stopwatch runs on their pre-93 LS400? Half or 1/4 tank of gas maybe?

mlevk

Hey LVangundy,

I don't mean to be critical about your mechanical ability but ...

GAPPING the plugs is a MUST unless you use plugs like BOSCH +4
which don't need to be gapped due to the 4 preset electrodes.

Did to torque the plugs when you installed them ? They can be over or under torqued , if under , they can come loose, thus loosing compression and mileage. I know people who did this and they actually pop off after a long while.

As for the PICS you posted , the lower balljoints, they look bad to me, leaking grease ! not a good thing. Most backyard mechanics know these items. I replaced mine 20K ago.About $91 each side.

If you had to ask about these things , then I suggest you try to learn from some one else before just doing it on your own.
I know we all have to learn sooner or later , but there's the right way and the wrong way.

Lvangundy

Hey - No, not offense taken. I agree with you..I didn't actually install the plugs myself! A family 'mechanic' did it, but most of his knowledge is based on old american cars. I didn't really do much except remove bolts. :-)

I would have preferred someone else installing them, but at the time $ was low and family member insisted on doing it.

I'd like to take it to the dealer, because I know they know exactly how to install those things correctly. Only problem, still short on $, and I know they will bill me a ton!

Ow that I think about it, the Torque master plugs come pre-gapped and I don't know if they are adjustable(?) They have that 4 piece tip.

JBrady

Hmmm... when you say powerband... the stock torque peak is at 4500rpm but it is fairly flat. Your time of 9 seconds seams a full second off the cars rated performance. You have done the basics without help so other things do come to mind including transmission. Torque converters can fail but other than a few Ford cars I cannot remember hearing about one. The clutch that locks the converter is another issue but this should not affect your acceleration rate.

Diagnosis is often a tricky thing. If the tranny is slipping your engine will rev higher than normal for a give rate of acceleration. If the engine is not responding that indicates either fuel, spark or mechanical obstruction.

Fuel: injector spray pattern (clean and balance or replace)
Fuel: filter (replace)
Fuel: contaminated fuel tank (clean)
Fuel: A/F ratio off (sensor problem, computer problem)
Spark: you have done all the basics, timing problem could still exist (sensor problem, computer problem)
Sensor: throttle position sensor
Sensor: air temperature
Sensor: 02 sensors
Sensor: engine temp
Sensor: MAF (mass air flow)
Sensor: MAP(manifold absolute pressure)
Mech: Exhaust: catalytic converter failure (replace)
Mech: Exhaust: resonator/muffler failure (replace)
Mech: Exhaust: damaged/crimped piping (replace)
Mech: Engine: worn camshaft (replace)
Mech: Engine: damaged valves (valvejob/replace)
Mech: Engine: excessive blowby (rebuild)
Mech: Engine: blown headgasket (replace)
Mech: Engine: excessive intake deposits (remove and clean)
Other possibilities...???

As you can see you are getting into the realm of a savy technician.

One thing you could consider is getting the car dyno tested. The car should make at least 160rwhp and more like 175rwhp (250hp engine less 70-80hp drivetrain loss) it will also give you the power curve. A loss of low end power, or mid range, or high end can all point to various possible problems. It also gives a good reference point. Dyno testing is usually $75 for 3 pulls but often can be done as part of a dyno "day" for as low as $35 for 2 pulls. Another option is a G-Tech or similar accelerometer testers than will give repeatable performance data.

meZoom!

do you notice any irregular pattern of accelerating and gear shifting? whenever my car gets screwy and slow, there are erradic rpm shifting points and tranny "buckling." but yeah i agree that your plugs can be a big issue......if not now in the future if they are not done right.