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1994 Corolla 1.8 DOHC Rough Idle

Hi, My bro and sister in law have had lots of trouble with their corolla. Its a 4 door front wheel drive automatic with 180K miles. Its the DX model and has the 1.8L 4 cylinder engine. It was missing and backfiring really bad and kept stalling. I bought some new NGK spark plugs and had to gap them myself, I dont remember what the gap was, maybe .32? Kragen gave me the spec. I helped him change them out, the old plugs were awful. The wires were old and not giving that great voltage. So we changed the wires the next weekend. No more stalling, no more missing, no more backfiring... The dis cap looked pretty good, no visable signs of wear. The air filter is brand new. I dont remember when the Oil was changed. Well they are still having a little bit of trouble. It idles ok, but every 15 seconds or there about at idle it will shutter really bad and almost die, occasionally it will stall. I am thinking this is an Air intake problem. Sorry I dont know much bout these cars. Personally I drive a 74GTO and hate new cars... a carb is easier to fix... What could the trouble be? I looked at the air inake and everything looks OK...

Reply to
sharks17
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Temporarily disconnect and block the vacuum hoses to the EGR valve and see if the problem goes away. If it does, remove and clean the EGR before re-connecting the vacuum hoses. If you cannot get enough crud cleaned out of the EGR to make the problem go away, then replace the EGR. Leaving the EGR disconnected will put the car out of compliance with emissions rules, so I do not recommend leaving it disconnected.

Reply to
Ray O

Thanks!!! OK You will laugh at me but I dont know were the EGR valve would be. I?m assuming its near the radiator...??? How much do you expect the part to be? Is just replacing it a good idea?

"Ray O" wrote: >

Reply to
sharks17

No, I only laugh at so-called automotive experts who cannot find the EGR valve. I would not expect someone who has not studied engine to know where an EGR valve is any more than I could tell the difference between a geranium and a begonia. ;-D

The exhaust gas recirculating (EGR) valve takes some exhaust gas and diverts it from the exhaust pipe back into the engine, along with fresh air and gas to reduce oxides of nitrogen emissions.

The EGR valve is located on the side of the engine that is furthest from the radiator. This diagram shows where to find it.:

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There are also links on checking it and how to replace it. Depending on which engine you have and whether you have an automatic or manual transmission, expect to pay around $160 for an aftermarket one.

Reply to
Ray O

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