90' corolla rough idle no power

[BigFan3]

I have a 1990 corolla with the 4afe motor.
It just started out as a little rough idle but now has got worse.
Now when it runs it's like someone is turning the ignition off and on and off and on back and forth.

When you give it gas it just sputters and shutters real bad.
It's like it's flooding out or not getting any gas... (?)

I changed the full filter (What a bitch)

changed the air filter.

Checked the timing and it's fine 10 bftc.

Also took the exhaust pipe off of the manifold to see if was the converter stopped up.
That wasn't it either.

All this done and it still does the same thing.

All spark plugs are getting fire to them but I haven't checked to see if the plug itself is firring.

It sputters and backfires when you "force" it down the road...

Now I'm thinking maybe the fuel injectors... but those are $120.00 each

Any help would be appreciated

[tashirosgt]

You should do a compression test, if you haven't already. If the engine is running on 3 cylinders, it would be rough like you describe. Another possibility is fuel pressure too low. It's hard to find on car store shelves, but you can get a banjo bolt that allows you to unscrew the cold start injector and measure fuel pressure there. (Don't do this while the engine is hot since if you have good pressure, gas squirts out as soon as you unscrew the injector.)

[BigFan3]

Thanks for the tips.
Short of buying a compression checker... I will have to pull each plug to see if it's firing.
I'll probably buy one in the next day or so if this doesn't work out.


Thanks again.

[DFBonnett]

Sounds like an ignition problem. How old are the cap, rotor, wires and plugs?

[Spud]

Check your distributor, cap and plug wires.Your car may also be running on 3 cylinders so have a look at the spark plugs.Lastly, try to get your fuel injectors checked.

[Spud]

Also check to see if your PCV valve needs changing.....

[BigFan3]

I think I got it fixed.

Spud gets the award for being the closest.

It was the injectors. I drove it to Advance Auto parts place and bought a can of injector cleaner.

Drove it hard for 2 days and it slowly got better and better.

Now it runs like a champ!


I'm thinking about dropping the gas tank and flushing it out.
But then again I'm think about leaving well enough alone...

Thanks for the responses folks. I appreciate it.

I'm sure I'll be back soon enough with something else....

Thanks again!

[DFBonnett]

Thanks for posting back with the fix. It's good to find out what actually did the trick.
Before you drop the tank, check it for a drain plug. I had an '82 Corona wagon once that had a drain plug on the tank. It's a lot easier to drop an empty tank.
FWIW
YMMV

[Spud]

Originally Posted by BigFan3

I think I got it fixed.

Spud gets the award for being the closest.

It was the injectors. I drove it to Advance Auto parts place and bought a can of injector cleaner.

Drove it hard for 2 days and it slowly got better and better.

Now it runs like a champ!


I'm thinking about dropping the gas tank and flushing it out.
But then again I'm think about leaving well enough alone...

Thanks for the responses folks. I appreciate it.

I'm sure I'll be back soon enough with something else....

Thanks again!

Glad to hear things are better!!!! Glad I could help if at least a little Thats what is so cool about this board, there are alot of peeps on here with a wealth of info and experience.I myself have gotten loads of info from just lurking around.Big ups to ALL TN members!!!!!

[toyotaspeed90]

well i wouldn't necessarily narrow it down to INJECTOR problems

fuel injector cleaners don't just 'clean' the system (by using a bunch of different chemicals).... they also bump up the octane rating and usually also act as a water remover in the tank

i would reccommend (before dropping the tank) dupming in a container of Iso Heet (around $2) and fill it up with gas from somewhere with good gas (ie, Texaco, Mobil1, or Chevron).... am/pm, sometimes exxon, and even costco (prob's with the ae92 and costco gas here) are lower grades of gas and CAN affect the fuel system

secondly.... don't replace the injectors.... look for a local shop that can clean/balance the injectors for you.... or go to www.witchhunter.com and send them your injectors.... usually under $100 and you end up with just as good as new injectors

[Spud]

Sounds reasonable to me.Thanks for the input toyotaspeed90!!!

[BigFan3]

OK it's back....
Doing the same thing as before.

I dumped in a can of 104+ octane boost and a can of gum out injector cleaner...

again it ran better and better...

Seems as long as I keep it full of High Octane gas , octane boost and injector cleaner it runs ok...

But as soon as I fill up with just regular gas and no additives it starts acting up again...

I found a place on the net where I can get injectors for $100.00 a set of four.

Thinking this is a gamble but seems to be the answer (??)

[91boz]

Put in a can of BG44K into your gas tank. Stongest thing out there to clean out your fuel system and injectors. Also cleans the upper cyliders and valves.

[REN69]

Have you thought that maybe its the cheap gas you're getting? Change gas stations, you could be getting bad gas.

[BigFan3]

"Put in a can of BG44K into your gas tank. Stongest thing out there to clean out your fuel system and injectors. Also cleans the upper cyliders and valves."

I'll try that but have my doubts as to it actually fixing the problem for good.

"Have you thought that maybe its the cheap gas you're getting? Change gas stations, you could be getting bad gas. "

No it's not the gas. I've tried B.P. Chevron, Texaco, Exxon.... all do the same.
all 93 octane... The only way it will run right is to keep 93 octane and add octane boost and injector cleaner....