[Daves9]

All, I've had some issues with stumbling during acceleration, I've cleaned the MAF as told, replaced the fuel filter, and the oxygen sensor. Still bad. The guy at Autozone said there's 2 sensors, I replaced the one right after the exhaust manifold, just behind the radiator but cannot find the second one, any suggestions.

It's a '93 wagon w/ 1.9 engine.

Thanks, Dave

 

[madmatt2024]

You don't have a second one and even if you did it would have no effect on your engine stumbling.

 

[zzyzzx]

How many miles are on the car?
Did you check for vacuum leaks? The PVC elbow goes bad like mad on these cars. Get a MityVac and use it to check for vacuum leaks.
How many miles are on the spark plugs? I hope you didn't put in Bosch plugs, they don't work good in these cars.

 

[Daves9]

The car has about 133 k miles, and the plugs have about 25 k on them, no they're not platinum ones either.
I did replace the PVC elbow twice now, they don't make them very sturdy, I ended up this last time, a month ago, using some rigid fuel line and it's doing well.
How do I use the MityVac to check for leaks? Can I hook up a shop-vac to the system instead?

Thanks for the help all, I appreciate it as I feel a little unsafe crossing intersections when it decides to hesitate and buck (I really don't want to get t-boned). Dave

 

[zzyzzx]

you should be using double platinum spark plugs like Autolite APP 5144's.

You connect up the MityVac to all vacuum devices and hoses, then operate the pump (hand held) and see if it holds vacuum.

 

[dave8338]

Plug wires. My guess is the #1 hole. :?

 

[zzyzzx]

I did replace the PVC elbow twice now, they don't make them very sturdy

The ones from the dealer hold up quite well

Check your TPS with a voltmeter (set on ohms).

 

[Daves9]

Hey Zzyzzx,

I have a Haynes manual, they only show testing the TPS in ohms for the 1.8 liter. Any suggestions for the 1.9, or is it the same?

Funny you should mention the TPS, I was thinking the same.

 

[Jeffescortlx]

So the plug wires are old?

It does sound like a air metering problem.
Does the car have EGR?

 

[zzyzzx]

Hey Zzyzzx,

I have a Haynes manual, they only show testing the TPS in ohms for the 1.8 liter. Any suggestions for the 1.9, or is it the same?

Funny you should mention the TPS, I was thinking the same.

You test it with an ohm meter the same way you would test any variable resistor. I use a wiring harness piece that I got at a junkyard and unplug the tps and plug in the test piece and read the ohms while moving the throttle (with the engine off). checking both sides to see if the resistance jumps around at any point (like a spike). If the TPS resistance acts like a dirty volume control knob, then it's bad. That's what happens to variable resistors when they get old, they wear out. It helps when you used to be an electronics technician like me.

 

[Daves9]

Thanks Zzyzzx, I too am an Elecronics Tech active duty working on USCG jet aircraft, just went over 22 years on Monday. I understand how a variable resistor works, I was wondering about the pin arrangement if it's the same as the 1.8, I'll figure it out.

Regarding the wires, I'm at work now and need to look at the maintenance log if they've been done once at home, I don't recall doing them myself and I've had the car since it was 110 k miles.

 

[zzyzzx]

Thanks Zzyzzx, I too am an Elecronics Tech active duty working on USCG jet aircraft, just went over 22 years on Monday. I understand how a variable resistor works, I was wondering about the pin arrangement if it's the same as the 1.8, I'll figure it out.

Standard 3 pin variable resistor. It isn't hard to figure out. If it matters, at 180K, I've got the original TPS in my 1995LX.

 

[pell]

I would say change the wires, my 95 was doing the same thing. I assumed the wires where OK just because they looked good but after changing them the car runs great.

 

[Daves9]

Well, took out the TPS, it semed to have a 'flat spot/open" in the middle of it's range while testing. So I sprayed it out with some avionics cleaner and cleaned the contacts, also cleaned the throttle body as well, re-installed and so far it seems to work without any stumbling.

I also went ahead and got new plug wires since they're the original ones, I felt it couldn't hurt. Thanks for the help, I really appreciate it.

 

[zzyzzx]

Well, took out the TPS, it semed to have a 'flat spot/open" in the middle of it's range while testing. So I sprayed it out with some avionics cleaner and cleaned the contacts, also cleaned the throttle body as well, re-installed and so far it seems to work without any stumbling.

I would not necessarily expect the spray stuff to have a long term effect.